Fused heterocyclic indane carboxamide cgrp receptor antagonists

ABSTRACT

The present invention is directed to fused heterocyclic indane carboxamide derivatives which are antagonists of CGRP receptors and useful in the treatment or prevention of diseases in which the CGRP is involved, such as migraine. The invention is also directed to pharmaceutical compositions comprising these compounds and the use of these compounds and compositions in the prevention or treatment of such diseases in which CGRP is involved.

BACKGROUND OF THE INVENTION

CGRP (Calcitonin Gene-Related Peptide) is a naturally occurring 37-amino acid peptide that is generated by tissue-specific alternate processing of calcitonin messenger RNA and is widely distributed in the central and peripheral nervous system. CGRP is localized predominantly in sensory afferent and central neurons and mediates several biological actions, including vasodilation. CGRP is expressed in alpha- and beta-forms that vary by one and three amino acids in the rat and human, respectively. CGRP-alpha and CGRP-beta display similar biological properties. When released from the cell, CGRP initiates its biological responses by binding to the CGRP receptor which is a heterodimer consisting of the G-protein coupled calcitonin-like receptor (CLR) in association with the single transmembrane protein known as receptor activity modifying protein 1 (RAMP₁). CGRP receptors are predominantly coupled to the activation of adenylyl cyclase and have been identified and pharmacologically evaluated in several tissues and cells, including those of brain, cardiovascular, endothelial, and smooth muscle origin.

CGRP is a potent neuromodulator that has been implicated in the pathology of cerebrovascular disorders such as migraine and cluster headache. In clinical studies, elevated levels of CGRP in the jugular vein were found to occur during migraine attacks (Goadsby et al. (1990) Ann. Neurol. 28, 183-187), salivary levels of CGRP are elevated in migraine subjects between (Bellamy et al. (2006) Headache 46, 24-33) and during attacks (Cady et al. (2009) Headache 49, 1258-1266), and CGRP itself has been shown to trigger migrainous headache (Lassen et al. (2002) Cephalalgia 22, 54-61). In clinical trials, the CGRP receptor antagonist BIBN4096BS has been shown to be effective in treating acute attacks of migraine (Olesen et al. (2004) New Engl. J. Med. 350, 1104-1110) and was able to prevent headache induced by CGRP infusion in a control group (Petersen et al. (2005) Clin. Pharmacol. Ther. 77, 202-213). The orally bioavailable CGRP receptor antagonist telcagepant has also shown antimigraine effectiveness in phase III clinical trials (Ho et al. (2008) Lancet 372, 2115-2123; Connor et al. (2009) Neurology 73, 970-977)

CGRP-mediated activation of the trigeminovascular system may play a key role in migraine pathogenesis. Additionally, CGRP activates receptors on the smooth muscle of intracranial vessels, leading to increased vasodilation, which is thought to contribute to headache pain during migraine attacks (Lance, Headache Pathogenesis: Monoamines, Neuropeptides, Purines and Nitric Oxide, Lippincott-Raven Publishers, 1997, 3-9). The middle meningeal artery, the principle artery in the dura mater, is innervated by sensory fibers from the trigeminal ganglion which contain several neuropeptides, including CGRP. Trigeminal ganglion stimulation in the cat resulted in increased levels of CGRP, and in humans, activation of the trigeminal system caused facial flushing and increased levels of CGRP in the external jugular vein (Goadsby et al. (1988) Ann. Neurol. 23, 193-196). Electrical stimulation of the dura mater in rats increased the diameter of the middle meningeal artery, an effect that was blocked by prior administration of CGRP(8-37), a peptide CGRP receptor antagonist (Williamson et al. (1997) Cephalalgia 17, 525-531). Trigeminal ganglion stimulation increased facial blood flow in the rat, which was inhibited by CGRP(8-37) (Escott et al. (1995) Brain Res. 669, 93-99). Electrical stimulation of the trigeminal ganglion in marmoset produced an increase in facial blood flow that could be blocked by the non-peptide CGRP receptor antagonist BIBN4096BS (Doods et al. (2000) Br. J. Pharmacol. 129, 420-423). Thus the vascular effects of CGRP may be attenuated, prevented or reversed by a CGRP receptor antagonist.

CGRP-mediated vasodilation of rat middle meningeal artery was shown to sensitize neurons of the trigeminal nucleus caudalis (Williamson et al., The CGRP Family: Calcitonin Gene-Related Peptide (CGRP), Amylin, and Adrenomedullin, Landes Bioscience, 2000, 245-247). Similarly, distention of dural blood vessels during migraine headache may sensitize trigeminal neurons. Some of the associated symptoms of migraine, including extra-cranial pain and facial allodynia, may be the result of sensitized trigeminal neurons (Burstein et al. (2000) Ann. Neurol. 47, 614-624). A CGRP antagonist may be beneficial in attenuating, preventing or reversing the effects of neuronal sensitization.

The ability of the compounds of the present invention to act as CGRP receptor antagonists makes them useful pharmacological agents for disorders that involve CGRP in humans and animals, but particularly in humans. Such disorders include migraine and cluster headache (Doods (2001) Curr. Opin. Invest. Drugs 2, 1261-1268; Edvinsson et al. (1994) Cephalalgia 14, 320-327); chronic tension type headache (Ashina et al. (2000) Neurology 14, 1335-1340); pain (Yu et al. (1998) Eur. J. Pharmacol. 347, 275-282); chronic pain (Hulsebosch et al. (2000) Pain 86, 163-175); neurogenic inflammation and inflammatory pain (Holzer (1988) Neuroscience 24, 739-768; Delay-Goyet et al. (1992) Acta Physiol. Scanda. 146, 537-538; Salmon et al. (2001) Nature Neurosci. 4, 357-358); eye pain (May et al. (2002) Cephalalgia 22, 195-196), tooth pain (Awawdeh et al. (2002) Int. Endocrin. J. 35, 30-36), non-insulin dependent diabetes mellitus (Molina et al. (1990) Diabetes 39, 260-265); vascular disorders; inflammation (Zhang et al. (2001) Pain 89, 265); arthritis, bronchial hyperreactivity, asthma, (Foster et al. (1992) Ann. NY Acad. Sci. 657, 397-404; Schini et al. (1994) Am. J. Physiol. 267, H2483-H2490; Zheng et al. (1993) J. Virol. 67, 5786-5791); shock, sepsis (Beer et al. (2002) Crit. Care Med. 30, 1794-1798); opiate withdrawal syndrome (Salmon et al. (2001) Nature Neurosci. 4, 357-358); morphine tolerance (Menard et al. (1996) J. Neurosci. 16, 2342-2351); hot flashes in men and women (Chen et al. (1993) Lancet 342, 49; Spetz et al. (2001) J. Urology 166, 1720-1723); allergic dermatitis (Wallengren (2000) Contact Dermatitis 43, 137-143); psoriasis; encephalitis, brain trauma, ischaemia, stroke, epilepsy, and neurodegenerative diseases (Rohrenbeck et al. (1999) Neurobiol. Dis. 6, 15-34); skin diseases (Geppetti and Holzer, Eds., Neurogenic Inflammation, 1996, CRC Press, Boca Raton, Fla.), neurogenic cutaneous redness, skin rosaceousness and erythema; tinnitus (Herzog et al. (2002) J. Membr. Biol. 189, 225); obesity (Walker et al. (2010) Endocrinology 151, 4257-4269); inflammatory bowel disease, irritable bowel syndrome, (Hoffman et al. (2002) Scand. J. Gastroenterol. 37, 414-422) and cystitis. Of particular importance is the acute or prophylactic treatment of headache, including migraine and cluster headache.

U.S. Pat. No. 7,390,798, granted Jun. 24, 2008 and U.S. Patent Publication No. US 2010/0179166, published Jul. 15, 2010, disclose carboxamide CGRP receptor antagonist. The present invention is directed to a distinct class of CGRP receptor antagonists as compared to earlier disclosed analogues, pharmaceutical compositions comprising them and their use in therapy.

SUMMARY OF THE INVENTION

The present invention is directed to fused heterocyclic indane carboxamide derivatives which are antagonists of CGRP receptors and useful in the treatment or prevention of diseases in which the CGRP is involved, such as migraine. The invention is also directed to pharmaceutical compositions comprising these compounds and the use of these compounds and compositions in the prevention or treatment of such diseases in which CGRP is involved.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is directed to a genus of compounds of Formula I:

or a pharmaceutically acceptable salt thereof, wherein: X is selected from C(R⁴) or N; Y is selected from C(R⁵) or N; R² is selected from hydrogen and C₁₋₄alkyl; R¹ is selected from the group consisting of: (1) C₁₋₆alkyl, optionally substituted with one or more substituents as allowed by valence independently selected from the group consisting of: F, Cl, Br, hydroxy and C₁₋₄alkoxy, (2) C₃₋₆cycloalkyl, optionally substituted with one or more substituents as allowed by valence independently selected from the group consisting of: F, Cl, Br, hydroxy and C₁₋₄alkoxy, and

wherein R⁶, R⁷, R⁸, R⁹ and R¹⁰ are independently selected from the group consisting of hydrogen, methyl, F, Cl and Br; R³ is selected from the group consisting of: (1) hydrogen; (2) C₁₋₆alkyl, optionally substituted with one or more substituents as allowed by valence independently selected from the group consisting of F, amino, hydroxy and C₁₋₄alkoxy, said C₁₋₄alkoxy optionally substituted with hydroxy; (3) C₃₋₆cycloalkyl or a 5- or 6-membered heterocyclyl containing 1 to 3 heteroatoms selected from S, O and N, said C₃₋₆cycloalkyl and heterocyclyl optionally substituted with one or more substituents as allowed by valence independently selected from the group consisting of: F and —CF₃; and (4) phenyl; R⁴ is hydrogen or methyl; and R⁵ is hydrogen, F or CN.

Within the genus, the invention encompasses a first sub-genus of compounds of Formula I, or a pharmaceutically acceptable salt thereof, wherein Y is CH.

Also within the genus, the invention encompasses a second sub-genus of compounds of Formula I, or a pharmaceutically acceptable salt thereof, wherein Y is N.

Also within the genus, the invention encompasses a third sub-genus of compounds of Formula I, or a pharmaceutically acceptable salt thereof, wherein X is CH.

Also within the genus, the invention encompasses a fourth sub-genus of compounds of Formula I, or a pharmaceutically acceptable salt thereof, wherein X is N.

Also within the genus, the invention encompasses a fifth sub-genus of compounds of Formula I, or a pharmaceutically acceptable salt thereof, wherein R³ is selected from: 2,2,2-trifluoroethyl, 3,3,3-trifluoropropyl, 1-hydroxy-1-methylethyl, 1-amino-1-methylethyl, 1-methoxy-1-methylethyl, 1-ethoxy-1-methylethyl and 1-(2-hydroxyethoxy)-1-methylethyl.

Also within the genus, the invention encompasses a sixth sub-genus of compounds of Formula I, or a pharmaceutically acceptable salt thereof, wherein R³ is selected from: cyclopropyl, 1-(trifluoromethyl)cyclopropyl, cyclopentyl and tetrahydropyranyl.

Also within the genus, the invention encompasses a seventh sub-genus of compounds of Formula I, or a pharmaceutically acceptable salt thereof, wherein R¹ is selected from phenyl and 2,3-difluorophenyl.

Also within the genus, the invention encompasses an eighth sub-genus of compounds of Formula I, or a pharmaceutically acceptable salt thereof, wherein R² is methyl.

Also within the genus, the invention encompasses a ninth sub-genus of compounds having Formula Ia

or a pharmaceutically acceptable salt thereof, wherein: R^(a) and R^(b) are both hydrogen or both F.

Within the ninth sub-genus, the invention encompasses a first class of compounds of Formula Ia, or a pharmaceutically acceptable salt thereof, wherein X is CH.

Within the first class, the invention encompasses a first sub-class of compounds of Formula Ia, or a pharmaceutically acceptable salt thereof, wherein R³ is selected from: 2,2,2-trifluoroethyl, 3,3,3-trifluoropropyl, 1-hydroxy-1-methylethyl, 1-amino-1-methylethyl, 1-methoxy-1-methyl ethyl, 1-ethoxy-1-methylethyl and 1-(2-hydroxyethoxy)-1-methylethyl.

Within the first sub-class, the invention encompasses a first group of compounds of Formula Ia, or a pharmaceutically acceptable salt thereof, wherein R^(a) and R^(b) are both hydrogen.

Within the ninth sub-genus, the invention encompasses a second class of compounds of Formula Ia, or a pharmaceutically acceptable salt thereof, wherein X is N═.

Within the second class, the invention encompasses a second sub-class of compounds of Formula Ia, or a pharmaceutically acceptable salt thereof, wherein R³ is selected from: 2,2,2-trifluoroethyl, 3,3,3-trifluoropropyl, 1-hydroxy-1-methylethyl, 1-amino-1-methylethyl, 1-methoxy-1-methylethyl, 1-ethoxy-1-methylethyl and 1-(2-hydroxyethoxy)-1-methylethyl.

Within the second sub-class, the invention encompasses a second group of compounds of Formula Ia, or a pharmaceutically acceptable salt thereof, wherein R^(a) and R^(b) are both hydrogen.

The invention also encompasses compounds of Formula Ia, or a pharmaceutically acceptable salt thereof, wherein Y is CH. The invention also encompasses compounds of Formula Ia, or a pharmaceutically acceptable salt thereof, wherein Y is N.

In another embodiment of the invention, R¹ is

R² is selected from hydrogen and methyl;

when R² is hydrogen then

R⁶ is selected from hydrogen, F or Cl;

R⁷ is selected from hydrogen, F or Cl;

R⁸ is hydrogen;

R⁹ is selected from hydrogen or F; and

R¹⁰ is selected from hydrogen, F or Cl;

except that at least two of R⁶, R⁷, R⁹ and R¹⁰ must be F or Cl unless R⁶ is Fin which case R⁷, R⁹ and R¹⁰ may all be hydrogen; and if R⁷ is Cl then R¹⁰ cannot be Cl; and

when R² is methyl then

R⁶ is selected from hydrogen, methyl, F, Cl, or Br;

R⁷ is selected from hydrogen, methyl, F or Cl;

R⁸ is selected from hydrogen or F;

R⁹ is selected from hydrogen or F; and

R¹⁰ is selected from hydrogen, methyl, F or Cl;

except that if R⁸ is F then at least three of R⁶, R⁷, R⁹ and R¹⁰ must be F; and if R⁷ is methyl or Cl then R¹⁰ cannot be methyl or Cl.

The invention also encompasses a compound selected from the examples that follow, or a pharmaceutically acceptable salt of any of the examples.

The invention also encompasses a pharmaceutical composition which comprises an inert carrier and the compound of Formula I, or a pharmaceutically acceptable salt thereof.

The invention also encompasses a method of treating headache in a mammalian patient in need of such treatment, which comprises administering to the patient a therapeutically effective amount of the compound of Formula I, or a pharmaceutically acceptable salt thereof. In a specific embodiment of the invention, the headache is migraine headache.

The invention also encompasses the use of a compound of Formula I, or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier, for the manufacture of a medicament for the treatment of headache. In a specific embodiment of the invention, the headache is migraine headache.

The invention is also directed to medicaments or pharmaceutical compositions for treating diseases or disorders in which CGRP is involved, such as migraine, which comprise a compound of Formula I, or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier.

The invention is also directed to the use of a compound of Formula I for treating diseases or disorders in which CGRP is involved, such as migraine.

The invention is further directed to a method for the manufacture of a medicament or a composition for treating diseases or disorders in which CGRP is involved, such as migraine, comprising combining a compound of any of Formula I with one or more pharmaceutically acceptable carriers.

The compounds of the present invention may contain one or more asymmetric centers and can thus occur as racemates and racemic mixtures, single enantiomers, diastereomeric mixtures and individual diastereomers. Additional asymmetric centers may be present depending upon the nature of the various substituents on the molecule. Each such asymmetric center will independently produce two optical isomers and it is intended that all of the possible optical isomers and diastereomers in mixtures and as pure or partially purified compounds are included within the ambit of this invention. Unless a specific stereochemistry is indicated, the present invention is meant to comprehend all such isomeric forms of these compounds.

The independent syntheses of these diastereomers or their chromatographic separations may be achieved as known in the art by appropriate modification of the methodology disclosed herein. Their absolute stereochemistry may be determined by the x-ray crystallography of crystalline products or crystalline intermediates which are derivatized, if necessary, with a reagent containing an asymmetric center of known absolute configuration.

If desired, racemic mixtures of the compounds may be separated so that the individual enantiomers are isolated. The separation can be carried out by methods well known in the art, such as the coupling of a racemic mixture of compounds to an enantiomerically pure compound to form a diastereomeric mixture, followed by separation of the individual diastereomers by standard methods, such as fractional crystallization or chromatography. The coupling reaction is often the formation of salts using an enantiomerically pure acid or base. The diasteromeric derivatives may then be converted to the pure enantiomers by cleavage of the added chiral residue. The racemic mixture of the compounds can also be separated directly by chromatographic methods utilizing chiral stationary phases, which methods are well known in the art.

Alternatively, any enantiomer of a compound may be obtained by stereoselective synthesis using optically pure starting materials or reagents of known configuration by methods well known in the art.

In the compounds of Formula I, the atoms may exhibit their natural isotopic abundances, or one or more of the atoms may be artificially enriched in a particular isotope having the same atomic number, but an atomic mass or mass number different from the atomic mass or mass number predominantly found in nature. The present invention is meant to include all suitable isotopic variations of the compounds of generic Formula I. For example, different isotopic forms of hydrogen (H) include protium (¹H) and deuterium (²H). Protium is the predominant hydrogen isotope found in nature. Enriching for deuterium may afford certain therapeutic advantages, such as increasing in vivo half-life or reducing dosage requirements, or may provide a compound useful as a standard for characterization of biological samples. Isotopically-enriched compounds within generic Formula I can be prepared without undue experimentation by conventional techniques well known to those skilled in the art or by processes analogous to those described in the Schemes and Examples herein using appropriate isotopically-enriched reagents and/or intermediates.

Tautomers of compounds defined in Formula I are also included within the scope of the present invention. For example, compounds including carbonyl CH₂C(O)— groups (keto forms) may undergo tautomerism to form hydroxyl CH═C(OH)— groups (enol forms). Both keto and enol faints are included within the scope of the present invention.

As used herein, “alkyl” is intended to mean linear or branched structures having no carbon-to-carbon double or triple bonds. Thus C₁₋₄alkyl is defined to identify the group as having 1, 2, 3 or 4 carbons in a linear or branched arrangement, such that C₁₋₄alkyl specifically includes, but is not limited to, methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl and tert-butyl. “Cycloalkyl” is an alkyl group, part or all of which forms a ring of three or more atoms.

The term “alkoxy,” as in C₁₋₄alkoxy, is intended to refer to include alkoxy groups of from 1 to 4 carbon atoms of a straight, branched and cyclic configuration. Examples include methoxy, ethoxy, propoxy, isopropoxy and the like.

The term “heterocyclyl”, as used herein except where noted, represents a stable 5- or 6-membered monocyclic heterocyclic ring system which is fully or partially saturated, and which consists of carbon atoms and from one to three heteroatoms selected from the group consisting of N, O and S, and wherein the nitrogen and sulfur heteroatoms may optionally be oxidized, and the nitrogen heteroatom may optionally be quaternized. The heterocyclic ring may be attached at any heteroatom or carbon atom which results in the creation of a stable structure. Examples of such heterocyclic groups include, but are not limited to, pyrrolidine, tetrahydrofuran, tetrahydrothiophene, imidazolidine, pyrazolidine, oxazolidine, isoxazolidine, thiazolidine, isothiazolidine, dioxolane, oxathiolane, dithiolane, piperidine, tetarhydropyran, thiane, piperazine, morpholine, dithiane, dioxane and the like.

As is well understood by one having ordinary skill in the art, “F” means fluoro, “Cl” means chloro and “Br” means bromo.

The phrase “pharmaceutically acceptable” is employed herein to refer to those compounds, materials, compositions, and/or dosage forms which are, within the scope of sound medical judgment, suitable for use in contact with the tissues of human beings and animals without excessive toxicity, irritation, allergic response, or other problem or complication, commensurate with a reasonable benefit/risk ratio.

As used herein, “pharmaceutically acceptable salts” refer to derivatives wherein the parent compound is modified by making acid or base salts thereof. Salts in the solid form may exist in more than one crystal structure, and may also be in the form of hydrates. Examples of pharmaceutically acceptable salts include, but are not limited to, mineral or organic acid salts of basic residues such as amines; alkali or organic salts of acidic residues such as carboxylic acids; and the like. The pharmaceutically acceptable salts include the conventional non-toxic salts or the quaternary ammonium salts of the parent compound formed, for example, from non-toxic inorganic or organic acids. For example, such conventional non-toxic salts include those derived from inorganic acids such as hydrochloric, hydrobromic, sulfuric, sulfamic, phosphoric, nitric and the like; and the salts prepared from organic acids such as acetic, propionic, succinic, glycolic, stearic, lactic, malic, tartaric, citric, ascorbic, pamoic, maleic, hydroxymaleic, phenylacetic, glutamic, benzoic, salicylic, sulfanilic, 2-acetoxybenzoic, fumaric, toluenesulfonic, methanesulfonic, ethane disulfonic, oxalic, isethionic, and the like. Salts derived from inorganic bases include aluminum, ammonium, calcium, copper, ferric, ferrous, lithium, magnesium, manganic salts, manganous, potassium, sodium, zinc, and the like.

When the compound of the present invention is basic, salts may be prepared from pharmaceutically acceptable non-toxic acids, including inorganic and organic acids. Such acids include acetic, benzenesulfonic, benzoic, camphorsulfonic, citric, ethanesulfonic, fumaric, gluconic, glutamic, hydrobromic, hydrochloric, isethionic, lactic, maleic, malic, mandelic, methanesulfonic, mucic, nitric, pamoic, pantothenic, phosphoric, succinic, sulfuric, tartaric, p-toluenesulfonic acid, and the like. In one aspect of the invention the salts are citric, hydrobromic, hydrochloric, maleic, phosphoric, sulfuric, fumaric, and tartaric acids. It will be understood that, as used herein, references to the compounds of Formula I are meant to also include the pharmaceutically acceptable salts.

Exemplifying the invention is the use of the compounds disclosed in the Examples and herein. Specific compounds within the present invention include a compound which may be selected from the group consisting of the compounds disclosed in the following Examples and pharmaceutically acceptable salts thereof and individual diastereomers thereof.

The subject compounds are useful in a method of antagonism of CGRP receptors in a patient such as a mammal in need of such antagonism comprising the administration of an effective amount of the compound. The present invention is directed to the use of the compounds disclosed herein as antagonists of CGRP receptors. In addition to primates, especially humans, a variety of other mammals can be treated according to the method of the present invention.

Another embodiment of the present invention is directed to a method for the treatment, control, amelioration, or reduction of risk of a disease or disorder in which the CGRP receptor is involved in a patient that comprises administering to the patient a therapeutically effective amount of a compound that is an antagonist of CGRP receptors.

The present invention is further directed to a method for the manufacture of a medicament for antagonism of CGRP receptors activity in humans and animals comprising combining a compound of the present invention with a pharmaceutical carrier or diluent.

The subject treated in the present methods is generally a mammal, for example a human being, male or female, in whom antagonism of CGRP receptor activity is desired. The term “therapeutically effective amount” means the amount of the subject compound that will elicit the biological or medical response of a tissue, system, animal or human that is being sought by the researcher, veterinarian, medical doctor or other clinician. As used herein, the term “treatment” refers both to the treatment and to the prevention or prophylactic therapy of the mentioned conditions, particularly in a patient who is predisposed to such disease or disorder.

The term “composition” as used herein is intended to encompass a product comprising the specified ingredients in the specified amounts, as well as any product which results, directly or indirectly, from combination of the specified ingredients in the specified amounts. Such term in relation to pharmaceutical composition, is intended to encompass a product comprising the active ingredient(s), and the inert ingredient(s) that make up the carrier, as well as any product which results, directly or indirectly, from combination, complexation or aggregation of any two or more of the ingredients, or from dissociation of one or more of the ingredients, or from other types of reactions or interactions of one or more of the ingredients. Accordingly, the pharmaceutical compositions of the present invention encompass any composition made by admixing a compound of the present invention and a pharmaceutically acceptable carrier. By “pharmaceutically acceptable” it is meant the carrier, diluent or excipient must be compatible with the other ingredients of the formulation and not deleterious to the recipient thereof.

The present invention includes within its scope prodrugs of the compounds of this invention. In general, such prodrugs will be functional derivatives of the compounds of this invention which are readily convertible in vivo into the required compound. Thus, in the methods of treatment of the present invention, the terms “administration of” or “administering a” compound shall encompass the treatment of the various conditions described with the compound specifically disclosed or with a compound which may not be specifically disclosed, but which converts to the specified compound in vivo after administration to the patient. Conventional procedures for the selection and preparation of suitable prodrug derivatives are described, for example, in “Design of Prodrugs,” ed. H. Bundgaard, Elsevier, 1985. Metabolites of these compounds include active species produced upon introduction of compounds of this invention into the biological milieu.

The ability of the compounds of the present invention to act as CGRP receptor antagonists makes them useful pharmacological agents for disorders that involve CGRP in humans and animals, but particularly in humans.

The compounds of the present invention have utility in treating, preventing, ameliorating, controlling or reducing the risk of one or more of the following conditions or diseases: headache; migraine; cluster headache; chronic tension type headache; pain; chronic pain; neurogenic inflammation and inflammatory pain; neuropathic pain; eye pain; tooth pain; diabetes; non-insulin dependent diabetes mellitus; vascular disorders; inflammation; arthritis; bronchial hyperreactivity, asthma; shock; sepsis; opiate withdrawal syndrome; morphine tolerance; hot flashes in men and women; allergic dermatitis; psoriasis; encephalitis; brain trauma; epilepsy; neurodegenerative diseases; skin diseases; neurogenic cutaneous redness, skin rosaceousness and erythema; obesity; inflammatory bowel disease, irritable bowel syndrome, cystitis; and other conditions that may be treated or prevented by antagonism of CGRP receptors. Of particular importance is the acute or prophylactic treatment of headache, including migraine and cluster headache.

The subject compounds are further useful in a method for the prevention, treatment, control, amelioration, or reduction of risk of the diseases, disorders and conditions noted herein.

The subject compounds are further useful in a method for the prevention, treatment, control, amelioration, or reduction of risk of the aforementioned diseases, disorders and conditions in combination with other agents.

The compounds of the present invention may be used in combination with one or more other drugs in the treatment, prevention, control, amelioration, or reduction of risk of diseases or conditions for which compounds of Formula I or the other drugs may have utility, where the combination of the drugs together are safer or more effective than either drug alone. Such other drug(s) may be administered, by a route and in an amount commonly used therefor, contemporaneously or sequentially with a compound of Formula I. When a compound of Formula I is used contemporaneously with one or more other drugs, a pharmaceutical composition in unit dosage form containing such other drugs and the compound of Formula I is preferred. However, the combination therapy may also include therapies in which the compound of Formula I and one or more other drugs are administered on different overlapping schedules. It is also contemplated that when used in combination with one or more other active ingredients, the compounds of the present invention and the other active ingredients may be used in lower doses than when each is used singly. Accordingly, the pharmaceutical compositions of the present invention include those that contain one or more other active ingredients, in addition to a compound of Formula I.

For example, the present compounds may be used in conjunction with an an anti-migraine agent, such as ergotamine and dihydroergotamine, or other serotonin agonists, especially a 5-HT_(1B/1D) agonist, for example sumatriptan, naratriptan, zolmitriptan, eletriptan, almotriptan, frovatriptan, donitriptan, and rizatriptan, a 5-HT_(1D) agonist such as PNU-142633 and a 5-HT_(1F) agonist such as LY334370; a cyclooxygenase inhibitor, such as a selective cyclooxygenase-2 inhibitor, for example rofecoxib, etoricoxib, celecoxib, valdecoxib or paracoxib; a non-steroidal anti-inflammatory agent or a cytokine-suppressing anti-inflammatory agent, for example with a compound such as ibuprofen, ketoprofen, fenoprofen, naproxen, indomethacin, sulindac, meloxicam, piroxicam, tenoxicam, lornoxicam, ketorolac, etodolac, mefenamic acid, meclofenamic acid, flufenamic acid, tolfenamic acid, diclofenac, oxaprozin, apazone, nimesulide, nabumetone, tenidap, etanercept, tolmetin, phenylbutazone, oxyphenbutazone, diflunisal, salsalate, olsalazine or sulfasalazine and the like; or glucocorticoids. Similarly, the instant compounds may be administered with an analgesic such as aspirin, acetaminophen, phenacetin, fentanyl, sufentanil, methadone, acetyl methadol, buprenorphine or morphine.

Additionally, the present compounds may be used in conjunction with an interleukin inhibitor, such as an interleukin-1 inhibitor; an NK-1 receptor antagonist, for example aprepitant; an NMDA antagonist; an NR2B antagonist; a bradykinin-1 receptor antagonist; an adenosine A1 receptor agonist; a sodium channel blocker, for example lamotrigine; an opiate agonist such as levomethadyl acetate or methadyl acetate; a lipoxygenase inhibitor, such as an inhibitor of 5-lipoxygenase; an alpha receptor antagonist, for example indoramin; an alpha receptor agonist; a vanilloid receptor antagonist; a renin inhibitor; a granzyme B inhibitor; a substance P antagonist; an endothelin antagonist; a norepinephrin precursor; anti-anxiety agents such as diazepam, alprazolam, chlordiazepoxide and chlorazepate; serotonin 5HT₂ receptor antagonists; opiod agonists such as codeine, hydrocodone, tramadol, dextropropoxyphene and febtanyl; an mGluR5 agonist, antagonist or potentiator; a GABA A receptor modulator, for example acamprosate calcium; nicotinic antagonists or agonists including nicotine; muscarinic agonists or antagonists; a selective serotonin reuptake inhibitor, for example fluoxetine, paroxetine, sertraline, duloxetine, escitalopram, or citalopram; an antidepressant, for example amitriptyline, nortriptyline, clomipramine, imipramine, venlafaxine, doxepin, protriptyline, desipramine, trimipramine, or imipramine; a leukotriene antagonist, for example montelukast or zafirlukast; an inhibitor of nitric oxide or an inhibitor of the synthesis of nitric oxide.

Also, the present compounds may be used in conjunction with gap junction inhibitors; neuronal calcium channel blockers such as civamide; AMPA/KA antagonists such as LY293558; sigma receptor agonists; and vitamin B2.

Also, the present compounds may be used in conjunction with ergot alkaloids other than ergotamine and dihydroergotamine, for example ergonovine, ergonovine, methylergonovine, metergoline, ergoloid mesylates, dihydroergocornine, dihydroergocristine, dihydroergocryptine, dihydro-α-ergocryptine, dihydro-β-ergocryptine, ergotoxine, ergocornine, ergocristine, ergocryptine, α-ergocryptine, β-ergocryptine, ergosine, ergostane, bromocriptine, or methysergide.

Additionally, the present compounds may be used in conjunction with a beta-adrenergic antagonist such as timolol, propanolol, atenolol, metoprolol or nadolol, and the like; a MAO inhibitor, for example phenelzine; a calcium channel blocker, for example flunarizine, diltiazem, amlodipine, felodipine, nisolipine, isradipine, nimodipine, lomerizine, verapamil, nifedipine, or prochlorperazine; neuroleptics such as olanzapine, droperidol, prochlorperazine, chlorpromazine and quetiapine; an anticonvulsant such as topiramate, zonisamide, tonabersat, carabersat, levetiracetam, lamotrigine, tiagabine, gabapentin, pregabalin or divalproex sodium; an anti-hypertensive such as an angiotensin II antagonist, for example losartan, irbesartin, valsartan, eprosartan, telmisartan, olmesartan, medoxomil, candesartan and candesartan cilexetil, an angiotensin I antagonist, an angiotensin converting enzyme inhibitor such as lisinopril, enalapril, captopril, benazepril, quinapril, perindopril, ramipril and trandolapril; or botulinum toxin type A or B.

The present compounds may be used in conjunction with a potentiator such as caffeine, an H2-antagonist, simethicone, aluminum or magnesium hydroxide; a decongestant such as oxymetazoline, epinephrine, naphazoline, xylometazoline, propylhexedrine, or levo-desoxy-ephedrine; an antitussive such as caramiphen, carbetapentane, or dextromethorphan; a diuretic; a prokinetic agent such as metoclopramide or domperidone; a sedating or non-sedating antihistamine such as acrivastine, azatadine, bromodiphenhydramine, brompheniramine, carbinoxamine, chlorpheniramine, clemastine, dexbrompheniramine, dexchlorpheniramine, diphenhydramine, doxylamine, loratadine, phenindamine, pheniramine, phenyltoloxamine, promethazine, pyrilamine, terfenadine, triprolidine, phenylephrine, phenylpropanolamine, or pseudoephedrine. The present compounds also may be used in conjunction with anti-emetics.

In an embodiment of the invention the present compounds are used in conjunction with an anti-migraine agent, such as: ergotamine or dihydroergotamine; a 5-HT₁ agonist, especially a 5-HT_(1B/1D) agonist, in particular, sumatriptan, naratriptan, zolmitriptan, eletriptan, almotriptan, frovatriptan, donitriptan, avitriptan and rizatriptan, and other serotonin agonists; and a cyclooxygenase inhibitor, such as a selective cyclooxygenase-2 inhibitor, in particular, rofecoxib, etoricoxib, celecoxib, valdecoxib or paracoxib.

The above combinations include combinations of a compound of the present invention not only with one other active compound, but also with two or more other active compounds. Likewise, compounds of the present invention may be used in combination with other drugs that are used in the prevention, treatment, control, amelioration, or reduction of risk of the diseases or conditions for which compounds of the present invention are useful. Such other drugs may be administered, by a route and in an amount commonly used therefore, contemporaneously or sequentially with a compound of the present invention. When a compound of the present invention is used contemporaneously with one or more other drugs, a pharmaceutical composition containing such other drugs in addition to the compound of the present invention is preferred. Accordingly, the pharmaceutical compositions of the present invention include those that also contain one or more other active ingredients, in addition to a compound of the present invention.

The weight ratio of the compound of the compound of the present invention to the other active ingredient(s) may be varied and will depend upon the effective dose of each ingredient. Generally, an effective dose of each will be used. Thus, for example, when a compound of the present invention is combined with another agent, the weight ratio of the compound of the present invention to the other agent will generally range from about 1000:1 to about 1:1000, or from about 200:1 to about 1:200. Combinations of a compound of the present invention and other active ingredients will generally also be within the aforementioned range, but in each case, an effective dose of each active ingredient should be used.

In such combinations the compound of the present invention and other active agents may be administered separately or in conjunction. In addition, the administration of one element may be prior to, concurrent to, or subsequent to the administration of other agent(s), and via the same or different routes of administration.

The compounds of the present invention may be administered by oral, parenteral (e.g., intramuscular, intraperitoneal, intravenous, ICY, intracisternal injection or infusion, subcutaneous injection, or implant), by inhalation spray, nasal, vaginal, rectal, sublingual, buccal or topical routes of administration and may be formulated, alone or together, in suitable dosage unit formulations containing conventional non-toxic pharmaceutically acceptable carriers, adjuvants and vehicles appropriate for each route of administration. In addition to the treatment of warm-blooded animals the compounds of the invention are effective for use in humans.

The pharmaceutical compositions for the administration of the compounds of this invention may conveniently be presented in dosage unit form and may be prepared by any of the methods well known in the art of pharmacy. All methods include the step of bringing the active ingredient into association with the carrier which constitutes one or more accessory ingredients. In general, the pharmaceutical compositions are prepared by uniformly and intimately bringing the active ingredient into association with a liquid carrier or a finely divided solid carrier or both, and then, if necessary, shaping the product into the desired formulation. In the pharmaceutical composition the active compound is included in an amount sufficient to produce the desired effect upon the process or condition of diseases. As used herein, the term “composition” is intended to encompass a product comprising the specified ingredients in the specified amounts, as well as any product which results, directly or indirectly, from combination of the specified ingredients in the specified amounts.

The pharmaceutical compositions containing the active ingredient may be in a form suitable for oral use, for example, as tablets, troches, lozenges, aqueous or oily suspensions, dispersible powders or granules, emulsions, solutions, hard or soft capsules, or syrups or elixirs. Compositions intended for oral use may be prepared according to any method known to the art for the manufacture of pharmaceutical compositions and such compositions may contain one or more agents selected from the group consisting of sweetening agents, flavoring agents, coloring agents and preserving agents in order to provide pharmaceutically elegant and palatable preparations. Tablets contain the active ingredient in admixture with non-toxic pharmaceutically acceptable excipients which are suitable for the manufacture of tablets. These excipients may be for example, inert diluents, such as calcium carbonate, sodium carbonate, lactose, calcium phosphate or sodium phosphate; granulating and disintegrating agents, for example, corn starch, or alginic acid; binding agents, for example starch, gelatin or acacia; and lubricating agents, for example magnesium stearate, stearic acid or talc. The tablets may be uncoated or they may be coated by known techniques to delay disintegration and absorption in the gastrointestinal tract and thereby provide a sustained action over a longer period. For example, a time delay material such as glyceryl monostearate or glyceryl distearate may be employed. They may also be coated by the techniques described in the U.S. Pat. Nos. 4,256,108; 4,166,452; and 4,265,874 to form osmotic therapeutic tablets for control release. Oral tablets may also be formulated for immediate release, such as fast melt tablets or wafers, rapid dissolve tablets or fast dissolve films.

Formulations for oral use may also be presented as hard gelatin capsules wherein the active ingredient is mixed with an inert solid diluent, for example, calcium carbonate, calcium phosphate or kaolin, or as soft gelatin capsules wherein the active ingredient is mixed with water or an oil medium, for example peanut oil, liquid paraffin, or olive oil.

Aqueous suspensions contain the active materials in admixture with excipients suitable for the manufacture of aqueous suspensions. Such excipients are suspending agents, for example sodium carboxymethylcellulose, methylcellulose, hydroxy-propylmethylcellulose, sodium alginate, polyvinyl-pyrrolidone, gum tragacanth and gum acacia; dispersing or wetting agents may be a naturally-occurring phosphatide, for example lecithin, or condensation products of an alkylene oxide with fatty acids, for example polyoxyethylene stearate, or condensation products of ethylene oxide with long chain aliphatic alcohols, for example heptadecaethyleneoxycetanol, or condensation products of ethylene oxide with partial esters derived from fatty acids and a hexitol such as polyoxyethylene sorbitol monooleate, or condensation products of ethylene oxide with partial esters derived from fatty acids and hexitol anhydrides, for example polyethylene sorbitan monooleate. The aqueous suspensions may also contain one or more preservatives, for example ethyl, or n-propyl, p-hydroxybenzoate, one or more coloring agents, one or more flavoring agents, and one or more sweetening agents, such as sucrose or saccharin.

Oily suspensions may be formulated by suspending the active ingredient in a vegetable oil, for example arachis oil, olive oil, sesame oil or coconut oil, or in a mineral oil such as liquid paraffin. The oily suspensions may contain a thickening agent, for example beeswax, hard paraffin or cetyl alcohol. Sweetening agents such as those set forth above, and flavoring agents may be added to provide a palatable oral preparation. These compositions may be preserved by the addition of an anti-oxidant such as ascorbic acid.

Dispersible powders and granules suitable for preparation of an aqueous suspension by the addition of water provide the active ingredient in admixture with a dispersing or wetting agent, suspending agent and one or more preservatives. Suitable dispersing or wetting agents and suspending agents are exemplified by those already mentioned above. Additional excipients, for example sweetening, flavoring and coloring agents, may also be present.

The pharmaceutical compositions of the invention may also be in the form of oil-in-water emulsions. The oily phase may be a vegetable oil, for example olive oil or arachis oil, or a mineral oil, for example liquid paraffin or mixtures of these. Suitable emulsifying agents may be naturally-occurring gums, for example gum acacia or gum tragacanth, naturally-occurring phosphatides, for example soy bean, lecithin, and esters or partial esters derived from fatty acids and hexitol anhydrides, for example sorbitan monooleate, and condensation products of the said partial esters with ethylene oxide, for example polyoxyethylene sorbitan monooleate. The emulsions may also contain sweetening and flavoring agents.

Syrups and elixirs may be formulated with sweetening agents, for example glycerol, propylene glycol, sorbitol or sucrose. Such formulations may also contain a demulcent, a preservative and flavoring and coloring agents.

The pharmaceutical compositions may be in the form of a sterile injectable aqueous or oleagenous suspension. This suspension may be formulated according to the known art using those suitable dispersing or wetting agents and suspending agents which have been mentioned above. The sterile injectable preparation may also be a sterile injectable solution or suspension in a non-toxic parenterally-acceptable diluent or solvent, for example as a solution in 1,3-butane diol. Among the acceptable vehicles and solvents that may be employed are water, Ringer's solution and isotonic sodium chloride solution. In addition, sterile, fixed oils are conventionally employed as a solvent or suspending medium. For this purpose any bland fixed oil may be employed including synthetic mono- or diglycerides. In addition, fatty acids such as oleic acid find use in the preparation of injectables.

The compounds of the present invention may also be administered in the form of suppositories for rectal administration of the drug. These compositions can be prepared by mixing the drug with a suitable non-irritating excipient which is solid at ordinary temperatures but liquid at the rectal temperature and will therefore melt in the rectum to release the drug. Such materials are cocoa butter and polyethylene glycols.

For topical use, creams, ointments, jellies, solutions or suspensions and the like, containing the compounds of the present invention are employed. Similarly, transdermal patches may also be used for topical administration.

The pharmaceutical composition and method of the present invention may further comprise other therapeutically active compounds as noted herein which are usually applied in the treatment of the above mentioned pathological conditions.

In the treatment, prevention, control, amelioration, or reduction of risk of conditions which require antagonism of CGRP receptor activity an appropriate dosage level will generally be about 0.01 to 500 mg per kg patient body weight per day which can be administered in single or multiple doses. A suitable dosage level may be about 0.01 to 250 mg/kg per day, about 0.05 to 100 mg/kg per day, or about 0.1 to 50 mg/kg per day. Within this range the dosage may be 0.05 to 0.5, 0.5 to 5 or 5 to 50 mg/kg per day. For oral administration, the compositions are may be provided in the form of tablets containing 1.0 to 1000 milligrams of the active ingredient, particularly 1.0, 5.0, 10.0, 15.0. 20.0, 25.0, 50.0, 75.0, 100.0, 150.0, 200.0, 250.0, 300.0, 400.0, 500.0, 600.0, 750.0, 800.0, 900.0, and 1000.0 milligrams of the active ingredient for the symptomatic adjustment of the dosage to the patient to be treated. The compounds may be administered on a regimen of 1 to 4 times per day, or may be administered once or twice per day.

When treating, preventing, controlling, ameliorating, or reducing the risk of headache, migraine, cluster headache, or other diseases for which compounds of the present invention are indicated, generally satisfactory results are obtained when the compounds of the present invention are administered at a daily dosage of from about 0.1 milligram to about 100 milligram per kilogram of animal body weight, given as a single daily dose or in divided doses two to six times a day, or in sustained release form. For most large mammals, the total daily dosage is from about 1.0 milligrams to about 1000 milligrams, or from about 1 milligrams to about 50 milligrams. In the case of a 70 kg adult human, the total daily dose will generally be from about 7 milligrams to about 350 milligrams. This dosage regimen may be adjusted to provide the optimal therapeutic response.

It will be understood, however, that the specific dose level and frequency of dosage for any particular patient may be varied and will depend upon a variety of factors including the activity of the specific compound employed, the metabolic stability and length of action of that compound, the age, body weight, general health, sex, diet, mode and time of administration, rate of excretion, drug combination, the severity of the particular condition, and the host undergoing therapy.

The utility of the compounds in accordance with the present invention as antagonists of CGRP receptor activity may be demonstrated by methodology known in the art. Inhibition of the binding of ¹²⁵I-CGRP to receptors and functional antagonism of CGRP receptors were determined as follows:

NATIVE RECEPTOR BINDING ASSAY: The binding of ¹²⁵I-CGRP to receptors in SK-N-MC cell membranes was carried out essentially as described (Edvinsson et al. (2001) Eur. J. Pharmacol. 415, 39-44). Briefly, membranes (25 μg) were incubated in 1 mL of binding buffer [10 mM HEPES, pH 7.4, 5 mM MgCl₂ and 0.2% bovine serum albumin (BSA)] containing 10 pM ¹²⁵I-CGRP and antagonist. After incubation at room temperature for 3 h, the assay was terminated by filtration through GFB glass fibre filter plates (PerkinElmer) that had been blocked with 0.5% polyethyleneimine for 3 h. The filters were washed three times with ice-cold assay buffer (10 mM HEPES, pH 7.4 and 5 mM MgCl₂), then the plates were air dried. Scintillation fluid (50 μL) was added and the radioactivity was counted on a Topcount (Packard Instrument). Data analysis was carried out by using Prism and the K_(i) was determined by using the Cheng-Prusoff equation (Cheng & Prusoff (1973) Biochem. Pharmacol. 22, 3099-3108).

RECOMBINANT RECEPTOR: Human CL receptor (Genbank accession number L76380) was subcloned into the expression vector pIREShyg2 (BD Biosciences Clontech) as a 5′NheI and 3′ PmeI fragment. Human RAMP1 (Genbank accession number AJ001014) was subcloned into the expression vector pIRESpuro2 (BD Biosciences Clontech) as a 5′NheI and 3′NotI fragment. HEK 293 cells (human embryonic kidney cells; ATCC #CRL-1573) were cultured in DMEM with 4.5 g/L glucose, 1 mM sodium pyruvate and 2 mM glutamine supplemented with 10% fetal bovine serum (FBS), 100 units/mL penicillin and 100 μg/mL streptomycin, and maintained at 37° C. and 95% humidity. Cells were subcultured by treatment with 0.25% trypsin with 0.1% EDTA in HBSS. Stable cell line generation was accomplished by co-transfecting 10 μg of DNA with 30 μg Lipofectamine 2000 (Invitrogen) in 75 cm² flasks. CL receptor and RAMP1 expression constructs were co-transfected in equal amounts. Twenty-four hours after transfection the cells were diluted and selective medium (growth medium+300 μg/mL hygromycin and 1 μg/mL puromycin) was added the following day. A clonal cell line was generated by single cell deposition utilizing a FACS Vantage SE (Becton Dickinson). Growth medium was adjusted to 150 μg/mL hygromycin and 0.5 μg/mL puromycin for cell propagation.

RECOMBINANT RECEPTOR BINDING ASSAY: Cells expressing recombinant human CL receptor/RAMP1 were washed with PBS and harvested in harvest buffer containing 50 mM HEPES, 1 mM EDTA and Complete™ protease inhibitors (Roche). The cell suspension was disrupted with a laboratory homogenizer and centrifuged at 48,000 g to isolate membranes. The pellets were resuspended in harvest buffer plus 250 mM sucrose and stored at 70° C. For binding assays, 20 μg of membranes were incubated in 1 mL binding buffer (10 mM HEPES, pH 7.4, 5 mM MgCl₂, and 0.2% BSA) for 3 h at room temperature containing 10 pM ¹²⁵I-hCGRP (GE Healthcare) and antagonist. The assay was terminated by filtration through 96-well GFB glass fiber filter plates (PerkinElmer) that had been blocked with 0.05% polyethyleneimine. The filters were washed 3 times with ice-cold assay buffer (10 mM HEPES, pH 7.4, and 5 mM MgCl₂). Scintillation fluid was added and the plates were counted on a Topcount (Packard). Non-specific binding was determined and the data analysis was carried out with the apparent dissociation constant (K_(i)) determined by using a non-linear least squares fitting the bound CPM data to the equation below:

$Y_{obsd} = \frac{\begin{matrix} {{\left( {Y_{\max} - Y_{\min}} \right)\left( {{\% I_{\max}} - {\%_{Imin}\text{/}100}} \right)} +} \\ {Y_{\min} + {\left( {Y_{\max} - Y_{\min}} \right)\left( {100 - {\% I_{\max}\text{/}100}} \right)}} \end{matrix}}{1 + \left( {\lbrack{Drug}\rbrack \text{/}{K_{i}\left( {1 + {\lbrack{Radiolabel}\rbrack \text{/}K_{d}}} \right)}^{nH}} \right.}$

Where Y is observed CPM bound, Y_(max) is total bound counts, Y_(min) is non specific bound counts, (Y_(max)−Y_(min)) is specific bound counts, % I_(max) is the maximum percent inhibition, % 1 min is the minimum percent inhibition, radiolabel is the probe, and the K_(d) is the apparent dissociation constant for the radioligand for the receptor as determined by hot saturation experiments.

RECOMBINANT RECEPTOR FUNCTIONAL ASSAY: Cells were resuspended in DMEM/F12 (Hyclone) supplemented with 1 g/L BSA and 300 μM isobutyl-methylxanthine. Cells were then plated in a 384-well plate (Proxiplate Plus 384; 509052761; Perkin-Elmer) at a density of 2,000 cells/well and incubated with antagonist for 30 min at 37° C. Human α-CGRP was then added to the cells at a final concentration of 1.2 nM and incubated an additional 20 min at 37° C. Following agonist stimulation, the cells were processed for cAMP determination using the two-step procedure according to the manufacturer's recommended protocol (HTRF cAMP dynamic 2 assay kit; 62AM4PEC; Cisbio). Raw data were transformed into concentration of cAMP using a standard curve then dose response curves were plotted and inflection point (IP) values were determined.

Examplary K_(i) values in the recombinant receptor binding assay for exemplary compounds of the invention are provided in the table below:

Example K_(i) (nM) 1.2  0.07 1.8  0.03 1.14 0.07 1.19 0.39 1.20 0.27 2.1  0.19

The following abbreviations are used throughout the text:

-   -   Me: methyl     -   Et: ethyl     -   t-Bu: tert-butyl     -   Bu: butyl     -   i-Pr: isopropyl     -   Ar: aryl     -   Ph: phenyl     -   Bn: benzyl     -   Py: pyridyl     -   Ac: acetylate     -   OAc: acetate     -   TFA: trifluoroacetic acid     -   HCl: hydrochloric acid     -   Boc: tert-butoxycarbonyl     -   EDC: N-(3-dimethylaminopropyl)-Y-ethylcarbodiimide hydrochloride     -   EDTA: ethylenediaminetetraacetic acid     -   DMF: N,N-dimethylformamide     -   THF: tetrahydrofuran     -   DMSO: dimethylsulfoxide     -   DMAP 4-dimethylaminopyridine     -   PDC pyridinium dichromate     -   HOAT 1-hydroxy-7-azabenzotriazole     -   Lawesson's     -   Reagent 2,4-bis-(4-methoxyphenyl)-1,3-dithia-2,4-diphosphetane         2,4-disulfide     -   DMEM: Dulbecco's Modified Eagle Medium (High Glucose)     -   FBS: fetal bovine serum     -   BSA: bovine serum albumin     -   PBS: phosphate-buffered saline     -   HEPES: N-(2-hydroxyethyl)piperazine-N′-(2-ethanesulfonic acid)     -   min: minutes     -   h: hours     -   aq: aqueous     -   HPLC: high performance liquid chromatography     -   LCMS: liquid chromatography-mass spectrometry     -   SFC: supercritical fluid chromatography

Methods for preparing the compounds of this invention are illustrated in the following Schemes and Examples. Starting materials are made according to procedures known in the art or as illustrated herein.

The compounds of the present invention can be prepared readily according to the following Schemes and specific examples, or modifications thereof, using readily available starting materials, reagents and conventional synthesis procedures. In these reactions, it is also possible to make use of variants which are themselves known to those of ordinary skill in this art but are not mentioned in greater detail. The general procedures for making the compounds claimed in this invention can be readily understood and appreciated by one skilled in the art from viewing the following Schemes.

While the invention has been described and illustrated with reference to certain particular embodiments thereof, those skilled in the art will appreciate that various adaptations, changes, modifications, substitutions, deletions, or additions of procedures and protocols may be made without departing from the spirit and scope of the invention. For example, effective dosages other than the particular dosages as set forth herein above may be applicable as a consequence of variations in the responsiveness of the mammal being treated for any of the indications with the compounds of the invention indicated above. Likewise, the specific pharmacological responses observed may vary according to and depending upon the particular active compounds selected or whether there are present pharmaceutical carriers, as well as the type of formulation and mode of administration employed, and such expected variations or differences in the results are contemplated in accordance with the objects and practices of the present invention. It is intended, therefore, that the invention be defined by the scope of the claims which follow and that such claims be interpreted as broadly as is reasonable.

Exemplifying the invention are the examples shown in the following table, which can be made according to the schemes and experimentals that follow, with modifications known to those skilled in the art. The requisite starting materials are described herein, commercially available, known in the literature, or readily synthesized by one skilled in the art. Straightforward protecting group strategies were applied in some routes.

TABLE 1

MS Example R¹ R² R³ X (M + 1) 1.1

H

CH 570.2326 1.2

H

CH 594.1931 1.3

H H CH 512.1   1.4

H Me CH 526.2060 1.5

H

CH 569.2460 1.6

H

CH 588.2198 1.7

H

N 571.2266 1.8

H

CH 584.2460 1.9

H

CH 596.2474 1.10

H

CH 558.2116 1.11

H

CH 594.2681 1.12

H

CH 552.2202 1.13

H

CH 548.2680 1.14

H

N 595.1860 1.15

H

CH 608.2094 1.16

H

N 559.2067 1.17

H

N 585.2222 1.18

H

CH 584.2   1.19

Me

N 599.2367 1.20

Me

CH 548.2679

TABLE 2

MS Example R¹ R² R³ X (M + 1) 2.1

Me

CH 549.2610 2.2

Me

CH 573.2219 2.3

Me

CH 563.2757

Reaction Schemes

The compounds of the present invention can be prepared readily according to the following Schemes and specific examples, or modifications thereof, using, readily available starting materials, reagents and conventional synthetic procedures. In these reactions, it is also possible to make use of variants which are themselves known to those of ordinary skill in this art but are not mentioned in greater detail. The general procedures for making the compounds claimed in this invention can be readily understood and appreciated by one skilled in the art from viewing the following Schemes.

Fused imidazo analogs of type 1.9 can be prepared according to Scheme 1. For R²═H, alkylation of various nitriles with iodoalanine derivative 1.2 give addition products which can be reduced with hydrogen to the amino esters and lactamized to intermediates 1.4. For R²=Me or other aliphatic groups, substituted ketones 1.3 can be alkylated with iodide 1.2 then treated with ammonia under reducing conditions to afford substituted lactams 1.4. Treatment with Lawesson's reagent yields the corresponding thioamides 1.5. Reaction of variously substituted amino alcohols 1.6 in the presence of mercury (II) chloride affords amidine alcohols 1.7 which are oxidized by pyridinium dichromate and undergo subsequent ring-closure to imidazoles 1.8. Deprotection and amide bond formation under standard conditions gives final targets 1.9.

The synthesis of pyrimidyl oxindole carboxylic acid substructures is shown in Scheme 2. Alkylation of dibromide 2.1 with oxindole 2.2 under basic conditions and subsequent chiral separation affords spirocycle 2.3. Dechlorination under buffered hydrogenation conditions and ester hydrolysis then affords acid 2.5.

(2R)-2′-Oxo-1,1′,2′,3-tetrahydrospiro[indene-2,3′-pyrrolo[2,3-b]pyridine]-5-carboxylic acid Step A: (2R)-5-Iodo-1,3-dihydrospiro[indene-2,3′-pyrrolo[2,3-b]pyridin]-2′(1′H)-one

A solution of sodium nitrite (107 g, 1.55 mol) in water (500 mL) was added dropwise over 15 min to a solution of (2R)-5-amino-1,3-dihydrospiro[indene-2,3′-pyrrolo[2,3-b]pyridin]-Z(1′H)-one (prepared according to the procedures described in WO2008/020902, 195 g, 0.776 mol) and p-toluenesulfonic acid (443 g, 2.33 mol) in acetonitrile (1.94 L) at 23° C. After stirring for 30 min, a solution of potassium iodide (322 g, 1.94 mol) in water (500 mL) was then added over 15 minutes. The resulting mixture was stirred at 23° C. for 40 minutes, then diluted with water (2 L) and basified by the addition of solid NaOH (98.0 g, 2.44 mol) with stirring. Iodine by-product was reduced by the addition of 10% aqueous sodium thiosulfate solution and stirring for an additional 30 minutes. The solids were collected by filtration, washed with water, and dried under nitrogen atmosphere to give the title compound, which was used without further purification. MS: m/z 363.1 (M+1).

Step B: Methyl (2R)-2′-oxo-1,1′,2′,3-tetrahydrospiro[indene-2,3′-pyrrolo[2,3-b]pyridine]-5-carboxylate

A solution of (2R)-5-iodo-1,3-dihydrospiro[indene-2,3′-pyrrolo[2,3-b]pyridin]-2′(1′H)-one (100.0 g, 276 mmol), sodium acetate (45.3 g, 552 mmol) and Pd(dppf)Cl₂-CH₂Cl₂ (11.3 g, 13.8 mmol) in a mixture of MeOH (1 L) and toluene (30 mL) was pressurized to 120 psi of CO at 23° C. and then heated at 80° C. for 12 h with stirring. The reaction mixture was diluted with water (1 L), and the precipitate collected by filtration, washed with water, and dried under nitrogen atmosphere to give the title compound, which was used without further purification.

MS: m/z=295.3 (M+1).

Step C: (2R)-2′-Oxo-1,1′,2′3-tetrahydrospiro[indene-2,3′-pyrrolo[2,3-b]pyridine]-5-carboxylic acid

A mixture of methyl (2R)-2′-oxo-1,1′,2′,3-tetrahydrospiro[indene-2,3′-pyrrolo[2,3-b]pyridine]-5-carboxylate (81.0 g, 276 mmol) and aqueous sodium hydroxide solution (5.52 N, 250 mL, 1.38 mol) in MeOH (2.5 L) was heated at reflux for 4 h. The mixture was allowed to cool to 23° C. before it was acidified to pH 2 with aqueous 1 N hydrochloric acid solution. The precipitate was filtered, washed with water, and dried under nitrogen atmosphere to give the title compound. MS: m/z=281.2 (M+1).

Intermediate 2

(2R)-6-oxo-1,3,6′,7′-tetrahydrospiro[indene-2,5′-pyrrolo[2,3-d]pyrimidine]-5-carboxylic acid Step A: Methyl (2R)-4′-chloro-6′-oxo-1,3,6′,7′-tetrahydrospiro[indene-2,5′-pyrrolo[2,3-d]pyrimidine]-5-carboxylate

To a solution of methyl 3,4-bis(bromomethyl)benzoate (5.0 g, 15.5 mmol) and 4-chloro-5,7-dihydro-6H-pyrrolo[2,3-d]pyrimidin-6-one (5.3 g, 31.1 mmol) in N,N-dimethylformamide (150 mL) was added cesium carbonate (10.1 g, 31.1 mmol). After 10 min, water was added and the mixture was extracted with ethyl acetate. The combined organic extracts were washed with water, brine, dried over magnesium sulfate, filtered and concentrated. Purification by silica gel chromatography (1% methanol/dichloromethane→5% methanol/dichloromethane) then a second silica gel purification (100% dichloromethane→75% dichloromethane/EtOAc gave the title compound as a racemic mixture (2.1 g). Chiral separation of the individual enantiomers was accomplished by use of HPLC using a 10 cm Chiral Pak® AD® column (60% EtOH/hexanes with 0.1% diethylamine to give the title compound (1^(st) eluting enantiomer, 0.9 g). MS 330.2 (M).

Step B: Methyl (2R)-6′-oxo-1,3,6′,7′-tetrahydrospiro[indene-2,5′-pyrrolo[2,3-d]pyrimidine]-5-carboxylate

To a solution of methyl (2R)-4′-chloro-6′-oxo-1,3,6′,7′-tetrahydrospiro[indene-2,5′-pyrrolo[2,3-d]pyrimidine]-5-carboxylate (860 mg, 2.61 mmol) and triethylamine (364 uL, 2.61 mmol) in 10 mL of EtOAc was added 2.6 g of 10% Pd—C in a Parr vessel. The reaction was placed on the Parr shaker at 50 psi H₂. After 16 h, the reaction was backfilled with nitrogen, filtered through celite and concentrated in vacuo to afford the title compound as a mixture with 1 eq. triethylamine hydrochloride (360 mg). MS 296.1 (M+1).

Step C: (2R)-6-oxo-1,3,6′,7′-tetrahydrospiro[indene-2,5′-pyrrolo[2,3-d]pyrimidine]-5-carboxylic acid

To a solution of a mixture of methyl (2R)-6′-oxo-1,3,6′,7′-tetrahydrospiro[indene-2,5′-pyrrolo[2,3-d]pyrimidine]-5-carboxylate (10 mg, 0.034 mmol) and triethylamine hydrochloride (0.034 mmol from previous step) in 1 mL of 1:1 THF/MeOH was added 1N LiOH (102 uL, 102 mmol). After 16 h, the reaction was neutralized to pH=7 with 3N HCl and then concentrated in vacuo. The crude material was azeotroped from benzene to afford the title compound as a mixture with 3 eq. of lithium chloride and 1 eq. triethylamine hydrochloride (13 mg). MS 282.1 (M+1). ¹H NMR (500 MHz, DMSO d₆): δ 11.57 (s, 1H); 8.69 (s, 1H); 8.11 (s, 1H); 7.84 (m, 2H); 7.40 (dd, J=8.3 Hz, 1H); 3.34-3.28 (m, 4H).

Example 1.2

(2R)—N-[(6S,8S)-6-(2,3-Difluorophenyl)-3-(2,2,2-trifluoroethyl)-5,6,7,8-tetrahydroimidazo[1,2-a]pyridin-8-yl]-2′-oxo-1,1′,2′,3-tetrahydrospiro[indene-2,3′-pyrrolo[2,3-b]pyridine]-5-carboxamide Step A: Methyl 2-[(tert-butoxycarbonyl)amino]-4-cyano-4-(2,3-difluorophenyl)butanoate

To a solution of (2,3-difluorophenyl)acetonitrile (18.6 g, 122 mmol) in N,N-dimethylformamide (243 mL) at 0° C. was added sodium hydride (60% dispersion in mineral oil) (4.37 g, 109 mmol). After 20 min, methyl N-(tert-butoxycarbonyl)-3-iodo-D-alaninate (20.0 g, 60.8 mmol) was added, and the resulting mixture stirred 50 min. Saturated aqueous sodium bicarbonate was added, and the mixture was warmed to ambient temperature. Water was added and the mixture was extracted with ethyl acetate (3×). The combined organic extracts were washed with water (3×), brine, dried over magnesium sulfate, filtered and concentrated. Purification by silica gel chromatography (100% hexanes→20% hexanes/ethyl acetate) gave the title compound (12.0 g). MS 377.3 (M+Na).

Step B: tea-Butyl [(3S,5S)-5-(2,3-difluorophenyl)-2-oxopiperidin-3-yl]carbamate

To a solution of methyl 2-[(tert-butoxycarbonyl)amino]-4-cyano-4-(2,3-difluorophenyl)butanoate (11.0 g, 31.0 mmol) in methanol (621 mL) was added palladium hydroxide on carbon powder (20% palladium, with moisture ca 60%) (5.45 g, 3.10 mmol). The mixture was pressurized to 50 psi under an atmosphere of hydrogen. After 90 min, the mixture was filtered and concentrated. Purification by chromatography (Chiral Pak® AD® column, 60% ethanol/hexanes with 0.1% diethylamine) gave the title compound (2.0 g). MS 349.3 (M+Na). ¹H NMR (500 MHz, CDCl₃): δ 7.11-6.96 (m, 3H); 5.87 (s, 1H); 5.47 (s, 1H); 4.22-4.16 (m, 1H); 3.63-3.52 (m, 2H); 3.38 (t, J=11.2 Hz, 1H); 2.70 (s, 1H); 2.09 (q, J=12.3 Hz, 1H); 1.45 (s, 9H).

Step C: tert-Butyl [(3S,5S)-5-(2,3-difluorophenyl)-2-thioxopiperidin-3-yl]carbamate

To a solution of tert-butyl [(3S,5S)-5-(2,3-difluorophenyl)-2-oxopiperidin-3-yl]carbamate (300 mg, 0.92 mmol) in toluene (9.2 mL) was added Lawesson's Reagent (190 mg, 0.47 mmol). The mixture was stirred at 40° C. After 16 h, the mixture was cooled to ambient temperature and saturated aqueous sodium bicarbonate was added. Water was added, and the mixture was extracted with ethyl acetate (3×). The combined organic extracts were washed with brine, dried over magnesium sulfate, filtered and concentrated. Purification by reverse phase chromatography (C-18, 90% water/acetonitrile 5% water/acetonitrile with 0.1% trifluoroacetic acid) gave the title compound (226 mg). MS 365.3 (M+Na).

Step D: tert-Butyl {(3S,5S)-5-(2,3-difluorophenyl)-2-[(4,4,4-trifluoro-2-hydroxybutyl)imino]piperidin-3-yl}carbamate

To a solution of tert-butyl[(3S,5S)-5-(2,3-difluorophenyl)-2-thioxopiperidin-3-yl]carbamate (75.0 mg, 0.219 mmol) in ethanol (2.19 mL) was added the hydrochloride salt of 1-amino-4,4,4-trifluorobutan-2-ol (98.0 mg, 0.548 mmol), mercury(II) chloride (77.0 mg, 0.285 mmol), and triethylamine (73.3 uL, 0.526 mmol). The mixture was stirred 10 min, filtered, and concentrated giving the crude title compound. MS 452.17 (M+1).

Step E: tent-Butyl [(6S,8S)-6-(2,3-difluorophenyl)-3-(2,2,2-trifluoroethyl)-5,6,7,8-tetrahydroimidazo[1,2-a]pyridin-8-yl]carbamate

To a solution of crude tert-butyl {(3S,5S)-5-(2,3-difluorophenyl)-2-[(4,4,4-trifluoro-2-hydroxybutyl)imino]piperidin-3-yl}carbamate (99.0 mg, 0.219 mmol) in acetonitrile (2.19 mL) was added pyridinium dichromate (247 mg, 0.657 mmol), and the mixture was stirred 2.5 h at 60° C. Pyridinium dichromate (392 mg, 1.04 mmol) was added and the resulting mixture stirred 72 h at 60° C. Pyridinium dichromate (300 mg, 0.797 mmol) was added and the resulting mixture stirred 4 h at 60° C. The mixture was cooled to ambient temperature and saturated aqueous sodium bicarbonate was added. Water was added, and the mixture was extracted with ethyl acetate (3×). The combined organic extracts were washed with brine, dried over magnesium sulfate, filtered and concentrated. Purification by reverse phase chromatography (C-18, 95% water/acetonitrile→15% water/acetonitrile with 0.1% trifluoroacetic acid) gave the title compound (59 mg). MS 432.2 (M+1).

Step F: (6S,8S)-6-(2,3-Difluorophenyl)-3-(2,2,2-trifluoroethyl)-5,6,7,8-tetrahydroimidazo[1,2-a]pyridin-8-amine

To a solution of tort-butyl[6S,8S)-6-(2,3-difluorophenyl)-3-(2,2,2-trifluoroethyl)-5,6,7,8-tetrahydroimidazo[1,2-a]pyridin-8-yl]carbamate (59.0 mg, 0.137 mmol) in dichloromethane (1.37 mL) was added trifluoroacetic acid (105 μL, 1.37 mmol), and the mixture was stirred 1 h. Saturated aqueous sodium bicarbonate was added. Water was added, and the mixture was extracted with ethyl acetate (3×). The combined organic extracts were washed with brine, dried over magnesium sulfate, filtered and concentrated. Purification by reverse phase chromatography (C-18, 95% water/acetonitrile→30% water/acetonitrile with 0.1% trifluoroacetic acid) gave the title compound (23 mg). MS 332.3 (M+1).

Step G: (2R)—N-[(6S,8S)-6-(2,3-Difluorophenyl)-3-(2,2,2-trifluoroethyl)-5,6,7,8-tetrahydroimidazo[1,2-a]pyridin-8-yl]-2′-oxo-1,1′,2′,3-tetrahydrospiro[indene-2,3′-pyrrolo[2,3-b]pyridine]-5-carboxamide

To a solution of (6S,8S)-6-(2,3-difluorophenyl)-3-(2,2,2-trifluoroethyl)-5,6,7,8-tetrahydroimidazo[1,2-a]pyridin-8-amine (7.0 mg, 0.023 mmol) in N,N-dimethylforinamide (105 μL) was added (2R)-2′-oxo-1,1′,2′,3-tetrahydrospiro[indene-2,3′-pyrrolo[2,3-b]pyridine]-5-carboxylic acid (6.5 mg, 0.023 mmol), 1-hydroxy-7-azabenzotriazole (0.3 mg, 2.1 μmol), N-methylmorpholine (2.56 μL, 0.023 mmol) and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (4.46 mg, 0.023 mmol). The mixture was stirred 25 min. Water was added, and the mixture was purified by reverse phase chromatography (C-18, 95% water/acetonitrile→15% water/acetonitrile with 0.1% trifluoroacetic acid) giving the title compound (10.5 mg). HRMS 594.1931 (M+1). ¹H NMR (500 MHz, DMSO): δ 11.10 (s, 1H); 8.84 (d, J=8.6 Hz, 1H); 8.07 (dd, J=5.3, 1.6 Hz, 1H); 7.83 (s, 1H); 7.79 (d, J=8.0 Hz, 1H); 7.40-7.36 (m, 2H); 7.32-7.28 (m, 2H); 7.22 (dd, J=7.3, 1.6 Hz, 1H); 6.92 (s, 1H); 6.88 (dd, J=7.3, 5.3 Hz, 1H); 4.34 (d, J=7.9 Hz, 1H); 3.80 (t, J=10.3 Hz, 4H); 3.40 (d, J=16.3 Hz, 2H); 3.19 (dd, J=16.4, 3.5 Hz, 2H); 2.33-2.29 (m, 2H).

Example 1.8

(2R)—N-[(6S,8S)-6-(2,3-Difluorophenyl)-3-(2-methoxypropan-2-yl)-5,6,7,8-tetrahydroimidazo[1,2-a]pyridin-8-yl]-2′-oxo-1,1′,2′,3-tetrahydrospiro[indene-2,3′-pyrrolo[2,3-b]pyridine]-5-carboxamide Step A: tert-Butyl {(3S,5S)-5-(2,3-difluorophenyl)-2-[(2-hydroxy-3-methoxy-3-methylbutyl)imino]piperidin-3-yl}carbamate

To a solution of tert-butyl[(3S,5S)-5-(2,3-difluorophenyl)-2-thioxopiperidin-3-yl]carbamate (400 mg, 1.17 mmol) in ethanol (11.7 mL) was added 1-amino-3-methoxy-3-methylbutan-2-ol (389 mg, 2.92 mmol) and mercury (II) chloride (412 mg, L52 mmol). The mixture was stirred 20 min, filtered, and concentrated giving the crude title compound. MS 442.2 (M+1).

Step B: tent-Butyl [(6S,8S)-6-(2,3-difluorophenyl)-3-(2-methoxypopan-2-yl)-5,6,7,8-tetrahydroimidazo[1,2-a]pyridin-8-yl]carbamate

To a solution of crude tert-butyl {(3S,5S)-5-(2,3-difluorophenyl)-2-[(2-hydroxy-3-methoxy-3-methylbutyl)imino]piperidin-3-yl}carbamate (706 mg, 1.60 mmol) in acetonitrile (16.0 mL) was added pyridinium dichromate (3.01 g, 7.99 mmol), and the mixture was stirred 30 min at 70° C. Pyridinium dichromate (3.01 g, 7.99 mmol) was added and the resulting mixture stirred 45 min at 70° C. Pyridinium dichromate (900 mg, 2.40 mmol) was added and the resulting mixture stirred 30 min at 70° C. The mixture was cooled to ambient temperature and saturated aqueous sodium bicarbonate was added. Water was added, and the mixture was extracted with ethyl acetate (3×). The combined organic extracts were washed with brine, dried over magnesium sulfate, filtered and concentrated. Purification by reverse phase chromatography (C-18, 90% water/acetonitrile→15% water/acetonitrile with 0.1% trifluoroacetic acid) gave the title compound (380 mg). MS 422.2 (M+1).

Step C: (6S,8S)-6-(2,3-Difluorophenyl)-3-(2-methoxypropan-2-yl)-5,6,7,8-tetrahydroimidazo[1,2-a]pyridin-8-amine

To a solution of text-butyl [(6S,8S)-6-(2,3-difluorophenyl)-3-(2-methoxypopan-2-yl)-5,6,7,8-tetrahydroimidazo[1,2-a]pyridin-8-yl]carbamate (380 mg, 0.90 mmol) in dichloromethane (9.0 mL) was added trifluoroacetic acid (2.08 mL, 27.0 mmol), and the mixture was stirred 40 min. Saturated aqueous sodium bicarbonate was added. Water was added, and the mixture was extracted with ethyl acetate (3×). The combined organic extracts were washed with brine, dried over magnesium sulfate, filtered and concentrated. Purification by reverse phase chromatography (C-18, 95% water/acetonitrile→25% water/acetonitrile with 0.1% trifluoroacetic acid) gave the title compound (180 mg). MS 322.2 (M+1).

Step D: (2R)—N-[(6S,8S)-6-(2,3-Difluorophenyl)-3-(2-methoxypropan-2-yl)-5,6,7,8-tetrahydroimidazo[1,2-a]pyridin-8-yl]-2′-oxo-1,1′,2′,3-tetrahydrospiro[indene-2,3′-pyrrolo[2,3-b]pyridine]-5-carboxamide

To a solution of (6S,8S)-6-(2,3-difluorophenyl)-3-(2-methoxypropan-2-yl)-5,6,7,8-tetrahydroimidazo[1,2-a]pyridin-8-amine (75.0 mg, 0.23 mmol) in N,N-dimethylformamide (2.33 mL) was added (2R)-T-oxo-1,1′,2′,3-tetrahydrospiro[indene-2,3′-pyrrolo[2,3-b]pyridine]-5-carboxylic acid (72.0 mg, 0.26 mmol), 1-hydroxy-7-azabenzotriazole (3.2 mg, 0.023 mmol), N-methylmorpholine (28.2 μL, 0.26 mmol) and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (49.2 mg, 0.26 mmol). The mixture was stirred 35 min. Water was added, and the mixture was purified by reverse phase chromatography (C-18, 95% water/acetonitrile→20% water/acetonitrile with 0.1% trifluoroacetic acid). Treatment with 2 M hydrochloric acid in diethyl ether gave the title compound as a hydrochloride salt (115 mg). HRMS 584.2475 (M+1). NMR (400 MHz, DMSO): δ 11.13 (s, 1H); 9.35 (d, J=8.0 Hz, 1H); 8.09 (dd, J=5.3, 1.6 Hz, 1H); 7.83-7.78 (m, 214); 7.68 (s, 1H); 7.47-7.41 (m, 2H); 7.35 (t, J=6.7 Hz, 1H); 7.32-7.26 (m, 1H); 7.25 (dd, J=7.3, 1.6 Hz, 1H); 6.90 (dd, J=7.3, 5.3 Hz, 1H); 5.65 (q, J=8.6 Hz, 1H); 4.66 (dd, J=12.7, 4.0 Hz, 1H); 4.14 (t, J=12.2 Hz, 1H); 4.02 (t, J=12.3 Hz, 1H); 3.43 (s, 1H); 3.39 (s, 1H); 3.23 (dd, J=16.5, 4.7 Hz, 2H); 3.08 (s, 3H); 2.47-2.41 (m, 1H); 2.40-2.32 (m, 1H); 1.55 (d, J=7.7 Hz, 6H).

Example 1.14

(2R)—N-[(6S,8S)-6-(2,3-Difluorophenyl)-3-(2,2,2-trifluoroethyl)-5,6,7,8-tetrahydr[1,2,4]triazolo[4,3-a]pyridin-8-yl]-2′-oxo-1,1′,2′,3-tetrahydrospiro[indene-2,3′-pyrrolo[2,3-b]pyridine]-5-carboxamide Step A: tert-Butyl [(3S,5S)-5-(2,3-difluorophenyl)-2-hydrazinylidenepiperidin-3-yl]carbamate

To a solution of tert-butyl [(3S,5S)-5-(2,3-difluorophenyl)-2-thioxopiperidin-3-yl]carbamate (100 mg, 0.29 mmol) in methanol (2.9 mL) was added hydrazine hydrate (55%, 780 μL, 8.76 mmol). The mixture was stirred 40 min, and then concentrated. Water was added, and the mixture was extracted with ethyl acetate (×3). The combined organic extracts were washed with brine, dried over magnesium sulfate, filtered and concentrated to give the crude title compound. MS 341.2 (M+1).

Step B: (6S,8S)-6-(2,3-Difluorophenyl)-3-(222-trifluoroethy)1-5,6,7,8-tetrahydro[1,2,4]triazolo[4,3-a]pyridine-8-amine

To a solution of crude tert-butyl [(3S,5S)-5-(2,3-difluorophenyl)-2-hydrazinylidenepiperidin-3-yl]carbamate (77.0 mg, 0.23 mmol) in dichloromethane (2.3 mL) was added triethylamine (38 μL, 0.27 mmol) and 3,3,3-trifluoropropanoyl chloride (39.8 mg, 0.27 mmol). The mixture stirred for 1 h. Saturated aqueous sodium bicarbonate was added. Water was added, and the mixture was extracted with ethyl acetate (3×). The combined organic extracts were washed with brine, dried over magnesium sulfate, filtered and concentrated. Acetonitrile (2.3 mL) added. The mixture stirred at 70° C. 1.5 h. The mixture was allowed to cool to ambient temperature. Trifluoroacetic acid (696 μL, 9.04 mmol) was added, and the mixture stirred 16 h. Purification by reverse chromatography (C-18, 95% water/acetonitrile→25% water/acetonitrile with 0.1% trifluoroacetic acid) gave the title compound (22 mg). MS 333.2 (M+1).

Step C: (2R)—N-[(6S,8S)-6-(2,3-Difluorophenyl)-3-(2,2,2-trifluoroethyl)-5,6,7,8-tetrahydr[1,2,4]triazolo[4,3-a]pyridin-8-yl]-2′-oxo-1,1′,2′,3-tetrahydrospiro[indene-2,3′-pyrrolo[2,3-b]pyridine]-5-carboxamide

To a solution of (6S,8S)-6-(2,3-difluorophenyl)-3-(2,2,2-trifluoroethy)1-5,6,7,8-tetrandro[1,2,4]triazolo[4,3-a]pyridine-8-amine (11.0 mg, 0.033 mmol) in N,N-dimethylformamide (331 μL) was added (2R)-2′-oxo-1,1′,2′,3-tetrahydrospiro[indene-2,3′-pyrrolo[2,3-b]pyridine]-5-carboxylic acid (10.2 mg, 0.36 mmol), 1-hydroxy-7-azabenzotriazole (0.5 mg, 3.3 μmol), N-methylmorpholine (4.0 μL, 0.036 mmol) and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (7.0 mg, 0.036 mmol). The mixture was stirred 30 min. Water was added, and the mixture was purified by reverse phase chromatography (C-18, 95% water/acetonitrile→15% water/acetonitrile with 0.1% trifluoroacetic acid) giving the title compound (9.6 mg). HRMS 595.1860 (M+1). ¹H NMR (400 MHz, DMSO): δ 11.11 (s, 1H); 9.03 (d, J=8.5 Hz, 1H); 8.07 (dd, J=5.3, 1.6 Hz, 1H); 7.86-7.76 (m, 2H); 7.44-7.37 (m, 2H); 7.32-7.26 (m, 2H); 7.22 (dd, J=7.3, 1.6 Hz, 1H); 6.88 (dd, J=7.3, 5.3 Hz, 1H); 5.63-5.53 (m, 1H); 4.51-4.40 (m, 1H); 4.13-4.02 (m, 2H); 3.88-3.82 (m, 2H); 3.41 (d, J=16.3 Hz, 2H); 3.20 (d, J=16.3 Hz, 2H); 2.39-2.26 (m, 2H).

Example 1.19

(2R)—N-{(5R,6S,8S)-5-Methyl-6-phenyl-3-[1-(trifluoromethyl)cyclopropyl]-5,6,7,8-tetrahydro[1,2,4]triazolo[4,3-a]pyridin-8-yl}-2′-oxo-1,1′,2′,3-tetrahydrospiro[indene-2,3′-pyrrolo[2,3-b]pyridine]-5-carboxamide Step A: Methyl 2-[(tert-butoxycarbonyl)amino]-4-(4-chlorophenyl)-5-oxohexanoate

To a solution of methyl N-(tert-butoxycarbonyl)-3-iodo-L-alaninate (215 g, 652 mmol) and 4-chlorophenylacetone (100 g, 593 mmol) in dry N,N-dimethylformamide (1.5 L) was added cesium carbonate (483 g, 1483 mmol) at room temperature. After 4 h, the mixture was then added to a stirring solution of pH 7 buffer and EtOAc. The aqeuous layer was extracted with EtOAc and the combined organics were washed with pH 7 buffer, dried over sodium sulfate, filtered and concentrated. The crude product was purified by silica gel chromatography (10% ethyl acetate/heptane→30% ethyl acetate/heptane) to provide the title compound as a mixture of diastereomers (150 g). MS 392.1 (M+Na).

Step B: tert-Butyl[5-(4-chlorophenyl)-6-methyl-2-oxopiperidin-3-yl]carbamate

To a solution of methyl 2-[(tert-butoxycarbonyl)amino]-4-(4-chlorophenyl)-5-oxohexanoate (21.6 g, 58.4 mmol) in methanol (200 mL) were added ammonium acetate (45.0 g, 58.4 mmol), acetic acid (50.2 mL, 876 mmol), and sodium cyanoborohydride (5.51 g, 88 mmol). The mixture was heated at 60° C. for a total of 4 h. The mixture was then allowed to cool to ambient temperature and sodium bicarbonate and water were added. The mixture was extracted with ethyl acetate (3×). The combined organic extracts were washed with brine, dried over magnesium sulfate, filtered and concentrated. Ethanol (240 mL) and potassium carbonate (40.4 g, 292 mmol) were added. The mixture was stirred 1.5 h at 60° C. to effect epimerization to the desired epimer. Water was added followed by extraction with ethyl acetate (3×). The combined organic extracts were washed with brine, dried over magnesium sulfate, filtered and concentrated. Purification by silica gel chromatography (100% dichloromethane→90% dichloromethane/methanol with 0.1% ammonium hydroxide) gave the title compound as a mixture of isomers (12.3 g). MS 361.2 (M+Na).

Step C: tert-Butyl[(3S,5S,6R)-6-methyl-2-oxo-5-phenylpiperidin-3-yl]carbamate

To a solution of tert-butyl[5-(4-chlorophenyl)-6-methyl-2-oxopiperidin-3-yl]carbamate (12.1 g, 35.7 mmol) in methanol (179 mL) was added 10% palladium on activated carbon (7.6 g, 7.14 mmol). The resulting mixture stirred 6.5 h under 1 atmosphere of hydrogen. The mixture was filtered and concentrated. Ethanol (180 mL), triethylamine (4.98 mL, 35.7 mmol) and 10% palladium on activated carbon (7.6 g, 7.14 mmol) added. Mixture was stirred 2 h 15 min under 50 psi hydrogen. The mixture was filtered and concentrated. Dichloromethane (350 mL), triethylamine (2.49 mL, 17.9 mmol), and di-tert-butyl dicarbonate (2.07 mL, 8.93 mmol) were added, and the mixture stirred 30 min. Saturated aqueous sodium bicarbonate was added and the mixture was extracted with dichloromethane (2×). The combined organic extracts were washed with brine, dried over magnesium sulfate, filtered and concentrated. Purification by silica gel chromatography (100% dichloromethane→90% dichloromethane/methanol with 0.1% ammonium hydroxide) gave the title compound as a mixture of isomers. The mixture was purified by HPLC (Chiral Pak® AD® column, 60% ethanol/hexanes with 0.1% diethylamine). Purification by reverse chromatography (C-18, 90% water/acetonitrile→5% water/acetonitrile with 0.1% trifluoroacetic acid) gave the title compound (2 g). MS 327.3 (M+Na).

Step D: tert-Butyl[(3S,5S,6R)-6-methyl-5-phenyl-2-thioxopiperidin-3-yl]carbamate

To a solution of tert-butyl[(3S,5S,6R)-6-methyl-2-oxo-5-phenylpiperidin-3-yl]carbamate (796 mg, 2.62 mmol) in toluene (26.2 mL) was added Lawesson's Reagent (539 mg, 1.33 mmol) and the resulting mixture stirred at 40° C. 16 h. The mixture was cooled to ambient temperature and concentrated. Purification by silica gel chromatography (100% hexanes→60% hexanes/ethyl acetate) gave the title compound (725 mg). MS 343.3 (M+Na).

Step E: tert-Butyl[(3S,5S,6R)-2-hydrazinylidene-6-methyl-5-phenylpiperidin-3-yl]carbamate

To a solution of tert-Butyl [(3S,5S,6R)-6-methyl-5-phenyl-2-thioxopiperidin-3-yl]carbamate (100 mg, 0.31 mmol) in methanol (3.1 mL) was added hydrazine hydrate (55%, 833 μL, 9.36 mmol). The mixture was stirred 75 min, and then concentrated. Saturated aqueous sodium bicarbonate was added, and the mixture was extracted with ethyl acetate (×3). The combined organic extracts were washed with brine, dried over magnesium sulfate, filtered and concentrated to give the crude title compound. MS 319.4 (M+1).

Step F: tert-Butyl{(5R,6S,8S)-5-methyl-6-phenyl-3-[1-(trifluoromethyl)cyclopropyl]-5,6,7,8-tetrahydro[1,2,4]triazolo[4,3-a]pyridine-8-yl}carbamate

To a solution of crude tert-butyl[(3S,5S,6R)-2-hydrazinylidene-6-methyl-5-phenylpiperidin-3-yl]carbamate (99 mg, 0.31 mmol) in dichloromethane (3.1 mL) was added 1-(trifluoromethyl)cyclopropanecarboxylic acid (58 mg, 0.37 mmol), 1-hydroxy-7-azabenzotriazole (4.3 mg, 0.031 mmol), N-methylmorpholine (82 μL, 0.75 mmol) and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (72 mg, 0.37 mmol). The mixture was stirred 1 h. Saturated aqueous bicarbonate was added, and the resulting mixture was extracted with ethyl acetate (3×). The combined organic extracts were washed with brine, dried over magnesium sulfate, filtered and concentrated. Acetonitrile (12.5 mL) and glacial acetic acid (18 μL, 0.31 mmol) were added and the resulting mixture stirred at 70° C. for 90 min. Saturated aqueous bicarbonate was added, and the resulting mixture was extracted with ethyl acetate (3×). The combined organic extracts were washed with brine, dried over magnesium sulfate, filtered and concentrated giving the crude title compound. MS 437.2 (M+1),

Step G: (5R,6S,8S)-5-Methyl-6-phenyl-3-[1-(trifluoromethyl)cyclopropyl]-5,6,7,8-tetrahydro[1,2,4]triazolo[4,3-a]pyridine-8-amine

To a solution of crude tert-butyl {(5R,6S,8S)-5-methyl-6-phenyl-3-[1-(trifluoromethyl)cyclopropyl]-5,6,7,8-tetrahydro[1,2,4]triazolo[4,3-a]pyridine-8-yl}carbamate (136 mg, 0.31 mmol) in dichloromethane (3.1 mL) was added trifluoroacetic acid (721 μL, 9.4 mmol) and the resulting mixture stirred 30 min. Saturated aqueous bicarbonate was added, and the resulting mixture was extracted with ethyl acetate (3×). The combined organic extracts were washed with brine, dried over magnesium sulfate, filtered and concentrated. Purification by reverse chromatography (C-18, 95% water/acetonitrile 25% water/acetonitrile with 0.1% trifluoroacetic acid) gave the title compound (38 mg). MS 337.2 (M+1).

Step H: (2R)—N-{(5R,6S,8S)-5-Methyl-6-phenyl-3-[1-(trifluoromethyl)cyclopropyl]-5,6,7,8-tetrahydro[1,2,4]triazolo[4,3-a]pyridin-8-yl}-2′-oxo-1,1′,2′,3-tetrahydrospiro[indene-2,3′-pyrrolo[2,3-b]pyridine]-5-carboxamide

To a solution of (5R,6S,8S)-5-methyl-6-phenyl-3-[1-(trifluoromethyl)cyclopropyl]-5,6,7,8-tetrahydro[1,2,4]triazolo[4,3-a]pyridine-8-amine (19.0 mg, 0.056 mmol) in N,N-dimethylformamide (565 μL) was added (2R)-2′-oxo-1,1′,2′,3-tetrahydrospiro[indene-2,3′-pyrrolo[2,3-b]pyridine]-5-carboxylic acid (19.0 mg, 0.68 mmol), 1-hydroxy-7-azabenzotriazole (0.77 mg, 5.7 μmol), N-methylmorpholine (14.9 μL, 0.136 mmol) and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (13.0 mg, 0.068 mmol). The mixture was stirred 30 min. Water was added, and the mixture was purified by reverse phase chromatography (C-18, 95% water/acetonitrile→15% water/acetonitrile with 0.1% trifluoroacetic acid) giving the title compound (21 mg). HRMS 599.2367 (M+1). ¹H NMR (400 MHz, DMSO): δ 11.12 (s, 1H); 9.19 (d, J=8.2 Hz, 1H); 8.08-8.05 (m, 1H); 7.85 (s, 1H); 7.82 (d, J=8.0 Hz, 1H); 7.41 (t, J=6.9 Hz, 3H); 7.36-7.27 (m, 3H); 7.23 (dd, J=7.3, 1.6 Hz, 1H); 6.89 (dd, J=7.3, 5.3 Hz, 1H); 5.43 (dt, J=10.7, 7.8 Hz, 1H); 4.69-4.61 (m, 1H); 3.70 (d, J=13.5 Hz, 1H); 3.43 (d, 16.3 Hz, 2H); 3.21 (d, J=16.3 Hz, 2H); 2.67-2.56 (m, 1H); 2.36-2.25 (m, 1H); 1.73 (d, J=10.3 Hz, 1H); 1.63-1.51 (m, 2H); 1.25 (d, J=9.3 Hz, 1H); 1.17 (t, J=6.5 Hz, 3H).

Example 1.20

(2R)—N-[(5R,6S,8S)-3-(2-Hydroxypropan-2-yl)-5-methyl-6-phenyl-5,6,7,8-tetrahydroimidazo[1,2-a]pyridin-8-yl]-2′-oxo-1,1′,2′,3-tetrahydrospiro[indene-2,3′-pyrrolo[2,3-b]pyridine]-5-carboxamide Step A: tert-Butyl{(3S,5S,6R)-2-[(2-hydroxy-3-methoxy-3-methylbutyl)imino]-6-methyl-5-phenylpiperidin-3-yl}carbamate

To a solution of tert-butyl[(3S,5S,6R)-6-methyl-5-phenyl-2-thioxopiperidin-3-yl]carbamate (150 mg, 0.47 mmol) in ethanol (4.7 mL) was added 1-amino-3-methoxy-3-methylbutan-2-ol (156 mg, 1.17 mmol), mercury (II) chloride (165 mg, 0.61 mmol), and triethylamine (163 μL, 1.17 mmol). The mixture was stirred 20 min, and then concentrated, giving the crude title compound. MS 420.4 (M+1).

Step B: tert-Butyl[(5R,6S,8S)-3-(2-methoxypropan-2-yl)-5-methyl-6-phenyl-5,6,7,8-tetrahydroimidazo[1,2-a]pyridine-8-yl]carbamate

To a solution of tert-butyl{(3S,5S,6R)-2-[(2-hydroxy-3-methoxy-3-methylbutyl)imino]-6-methyl-5-phenylpiperidin-3-yl}carbamate (196 mg, 0.47 mmol) in acetonitrile (4.7 mL) was added pyridinium dichromate (880 mg, 2.34 mmol), and the mixture was stirred 1 h at 70° C. The mixture was cooled to ambient temperature and saturated aqueous sodium bicarbonate was added. Water was added, and the mixture was extracted with ethyl acetate (3×). The combined organic extracts were washed with brine, dried over magnesium sulfate, filtered and concentrated. Purification by reverse phase chromatography (C-18, 95% water/acetonitrile→15% water/acetonitrile with 0.1% trifluoroacetic acid) gave the title compound (36 mg). MS 400.4 (M+1).

Step C: 2-[(5R,6S,8S)-8-Amino-5-methyl-6-phenyl-5,6,7,8-tetrahydroimidazo[1,2-a]pyridin-3-yl]propan-2-ol

To a solution of tert-butyl[(5R,6S,8S)-3-(2-methoxypropan-2-yl)-5-methyl-6-phenyl-5,6,7,8-tetrahyddrohnidazo[1,2-c]pyridine-8-yl]carbamate (36 mg, 0.090 mmol) in dioxane (0.9 mL) and water (0.9 mL) was added methanesulfonic acid (293 μL, 1.17 mmol). The mixture was stirred 2.5 h at 50° C. The mixture was cooled to ambient temperature and saturated aqueous sodium bicarbonate was added. The mixture was extracted with ethyl acetate (3×). The combined organic extracts were washed with brine, dried over magnesium sulfate, filtered and concentrated, giving the crude title compound (22.5 mg). MS 286.4 (M+1).

Step D: (2R)—N-[(5R,6S,8S)-3-(2-Hydroxypropan-2-yl)-5-methyl-6-phenyl-5,6,7,8-tetrahydroimidazo[1,2-a]pyridin-8-yl]-2′-oxo-1,1′,2′,3-tetrahydrospiro[indene-2,3′-pyrrolo[2,3-b]pyridine-5-carboxamide

To a solution of 2-[(5R,6S,8S)-8-amino-5-methyl-6-phenyl-5,6,7,8-tetrahydroimidazo[1,2-c]pyridin-3-yl]propan-2-ol (5.5 mg, 0.019 mmol) in N,N-dimethylformamide (771 μL) was added (2R)-2′-oxo-1,1′,2′,3-tetrahydrospiro[indene-2,3′-pyrrolo[2,3-b]pyridine]-5-carboxylic acid (6.5 mg, 0.23 mmol), 1-hydroxy-7-azabenzotriazole (0.3 mg, 1.9 μmol), N-methylmorpholine (5.1 μL, 0.046 mmol) and 1-(3-dimethylaminopropyl)-3-ethylcarbodimide hydrochloride (4.4 mg, 0.023 mmol). The mixture was stirred 15 min. Water was added, and the mixture was purified by reverse phase chromatography (C-18, 95% water/acetonitrile→15% water/acetonitrile with 0.1% trifluoroacetic acid) giving the title compound (5.3 mg). HRMS 548.2679 (M+1). ¹H NMR (400 MHz, DMSO): δ 11.11 (s, 1H); 8.95 (d, J=8.3 Hz, 1H); 8.08 (dd, J=5.3, 1.6 Hz, 1H); 7.83 (d, J=8.0 Hz, 1H); 7.42-7.37 (m, 4H); 7.34 (s, 2H); 7.32-7.27 (m, 2H); 7.22 (dd, J=7.3, 1.6 Hz, 1H); 6.88 (dd, J=7.3, 5.3 Hz, 1H); 5.33 (d, J=9.5 Hz, 1H); 4.88 (s, 1H); 3.42 (d, J=16.2 Hz, 2H); 3.24-3.16 (m, 3H); 2.68-2.66 (m, 1H); 2.33 (t, J=1.9 Hz, 1H); 1.90 (s, 1H); 1.53 (d, J=10.2 Hz, 6H); 1.21 (d, J=6.2 Hz, 3H).

Example 2.1

(2R)—N-[(5R,6S,8S)-3-(2-Hydroxypropan-2-yl)-5-methyl-6-phenyl-5,6,7,8-tetrahydroimidazo[1,2-a]pyridin-8-yl]-6′-oxo-1,3′,6′,7′-tetrahydrospiro[indene-2,5′-pyrrolo[2,3-d]pyrimidine]-5-carboxamide

To a solution of 2-[(5R,6S,8S)-8-amino-5-methyl-6-phenyl-5,6,7,8-tetrahydroimidazo[1,2-a]pyridin-3-yl]propan-2-ol (5 mg, 0.018 mmol) N,N-dimethylformamide (175 μL) was added (2R)-6′-oxo-1,3,6′,7′-tetrahydrospiro[indene-2,5′-pyrrolo[2,3-d]pyrimidine]-5-carboxylic acid (5 mg, 0.018 mmol), 1-hydroxy-7-azabenzotriazole (0.2 mg, 0.002 mmol), N-methylmorpholine (4.6 μL, 0.042 mmol) and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (4 mg, 0.021 mmol). The mixture was stirred 2 h. Water was added, and the mixture was purified by reverse phase chromatography (C-18, 85% water/acetonitrile→5% water/acetonitrile with 0.1% trifluoroacetic acid) giving the title compound (5.4 mg). HRMS 549.2610 (M+1). ¹H NMR (500 MHz, CDCl₃): δ 8.76 (s, 1H); 7.89 (s, 1H); 7.83-7.79 (m, 2H); 7.40-7.33 (m, 3H); 7.32-7.28 (m, 3H); 6.94 (s, 1H); 5.27-5.22 (m, 1H); 4.98-4.95 (m, 1H); 3.69-3.54 (m, 3H); 3.12 (q, 15.8 Hz, 2H); 2.91-2.88 (m, 1H); 2.63-2.59 (m, 1H); 1.70 (d, J=23.7 Hz, 6H); 1.33 (d, J=6.4 Hz, 3H). 

1. A compound of Formula I:

or a pharmaceutically acceptable salt thereof, wherein: X is selected from C(R⁴) or N; Y is selected from C(R⁵) or N; R² is selected from hydrogen and C₁₋₄alkyl; R¹ is selected from the group consisting of: (1) C₁₋₆alkyl, optionally substituted with one or more substituents as allowed by valence independently selected from the group consisting of: F, Cl, Br, hydroxy and C₁₋₄alkoxy, (2) C₃₋₆cycloalkyl, optionally substituted with one or more substituents as allowed by valence independently selected from the group consisting of: F, Cl, Br, hydroxy and C₁₋₄alkoxy, and

wherein R⁶, R⁷, R⁸, R⁹ and R¹⁰ are independently selected from the group consisting of: hydrogen, methyl, F, Cl and Br; R³ is selected from the group consisting of: (1) hydrogen; (2) C₁₋₆alkyl, optionally substituted with one or more substituents as allowed by valence independently selected from the group consisting of: F, amino, hydroxy and C₁₋₄alkoxy, said C₁₋₄alkoxy optionally substituted with hydroxy; (3) C₃₋₆cycloalkyl or a 5- or 6-membered heterocyclyl containing 1 to 3 heteroatoms selected from S, O and N, said C₃₋₆cycloalkyl and heterocyclyl optionally substituted with one or more substituents as allowed by valence independently selected from the group consisting of: F and —CF₃; and (4) phenyl; R⁴ is hydrogen or methyl; and R⁵ is hydrogen, F or CN.
 2. The compound of claim 1, or a pharmaceutically acceptable salt thereof, wherein Y is CH.
 3. The compound of claim 1, or a pharmaceutically acceptable salt thereof, wherein X is CH.
 4. The compound of claim 1, or a pharmaceutically acceptable salt thereof, wherein X is N.
 5. The compound of claim 1, or a pharmaceutically acceptable salt thereof, wherein R³ is selected from: 2,2,2-trifluoroethyl, 3,3,3-trifluoropropyl, 1-hydroxy-1-methylethyl, 1-amino-1-methylethyl, 1-methoxy-1-methylethyl, 1-ethoxy-1-methylethyl and 1-(2-hydroxyethoxy)-1-methylethyl.
 6. The compound of claim 1, or a pharmaceutically acceptable salt thereof, wherein R³ is selected from: cyclopropyl, 1-(trifluoromethyl)cyclopropyl, cyclopentyl and tetrahydropyranyl.
 7. The compound of claim 1, or a pharmaceutically acceptable salt thereof, wherein R¹ is selected from phenyl and 2,3-difluorophenyl.
 8. The compound of claim 1, or a pharmaceutically acceptable salt thereof, wherein R² is methyl.
 9. The compound of claim 1 having Formula Ia

or a pharmaceutically acceptable salt thereof, wherein: R^(a) and R^(b) are both hydrogen or both F.
 10. The compound of claim 9, or a pharmaceutically acceptable salt thereof, wherein X is CH.
 11. The compound of claim 10, or a pharmaceutically acceptable salt thereof, wherein R³ is selected from: 2,2,2-trifluoroethyl, 3,3,3-trifluoropropyl, 1-hydroxy-1-methylethyl, 1-amino-1-methylethyl, 1-methoxy-1-methylethyl, 1-ethoxy-1-methylethyl and 1-(2-hydroxyethoxy)-1-methylethyl.
 12. The compound of claim 11, or a pharmaceutically acceptable salt thereof, wherein R^(a) and R^(b) are both hydrogen.
 13. The compound of claim 9, or a pharmaceutically acceptable salt thereof, wherein X is N.
 14. The compound of claim 13, or a pharmaceutically acceptable salt thereof, wherein R³ is selected from: 2,2,2-trifluoroethyl, 3,3,3-trifluoropropyl, 1-hydroxy-1-methylethyl, 1-amino-1-methylethyl, 1-methoxy-1-methylethyl, 1-ethoxy-1-methylethyl and 1-(2-hydroxyethoxy)-1-methylethyl.
 15. The compound of claim 14, or a pharmaceutically acceptable salt thereof, wherein R^(a) and R^(b) are both hydrogen.
 16. A compound of claim 1, selected from one of the following tables:

R¹ R² R³ X

H

CH

H

CH

H H CH

H Me CH

H

CH

H

CH

H

N

H

CH

H

CH

H

CH

H

CH

H

CH

H

CH

H

N

H

CH

H

N

H

N

H

CH

Me

N

Me

CH

R¹ R² R³ X

Me

CH

Me

CH

Me

CH

or a pharmaceutically acceptable salt of any of the foregoing compounds.
 17. A pharmaceutical composition which comprises an inert carrier and the compound of claim 1, or a pharmaceutically acceptable salt thereof.
 18. A method of treating headache in a mammalian patient in need of such treatment, which comprises administering to the patient a therapeutically effective amount of the compound of claim 1, or a pharmaceutically acceptable salt thereof.
 19. The method of claim 18, wherein the headache is migraine headache. 20-21. (canceled) 